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		<h1 id="title">Selectors Level 3</h1>

		<h2 class="no-num no-toc" id="longstatus-date">W3C Recommendation
			29 September 2011</h2>

		<dl>
			<dt>This version:</dt>
			<dd>
				<a href="http://www.w3.org/TR/2011/REC-css3-selectors-20110929/">
					http://www.w3.org/TR/2011/REC-css3-selectors-20110929/</a>
				<!-- <a href="http://dev.w3.org/csswg/selectors3">
						 http://dev.w3.org/csswg/selectors3</a> -->

			</dd>
			<dt>Latest version:</dt>
			<dd>
				<a href="http://www.w3.org/TR/css3-selectors/">
					http://www.w3.org/TR/css3-selectors/</a>

			</dd>
			<dt>Latest Selectors specification:</dt>
			<dd>
				<a href="http://www.w3.org/TR/selectors/">
					http://www.w3.org/TR/selectors/</a>

			</dd>
			<dt>Previous version:</dt>
			<dd>
				<a href="http://www.w3.org/TR/2009/PR-css3-selectors-20091215/">
					http://www.w3.org/TR/2009/PR-css3-selectors-20091215/</a>

			</dd>
			<dt>
				<a name="editors-list"></a>Editors:

			</dt>
			<dd class="vcard">
				<a class="url fn" href="http://www.tantek.com/" lang="tr">Tantek
					Çelik</a> (Invited Expert)

			</dd>
			<dd class="vcard">
				<a class="url fn" href="http://fantasai.inkedblade.net/contact">Elika
					J. Etemad</a> (Invited Expert)

			</dd>
			<dd class="vcard">
				<span class="fn">Daniel Glazman</span> (Disruptive Innovations SARL)

			</dd>
			<dd class="vcard">
				<a class="url fn" href="mailto:ian@hixie.ch">Ian Hickson</a> (<span
					class="company"><a href="http://www.google.com/">Google</a></span>)

			</dd>
			<dd class="vcard">
				<span class="fn">Peter Linss</span> (former editor, <span
					class="company"><a href="http://www.netscape.com/">Netscape/AOL</a></span>)

			</dd>
			<dd class="vcard">
				<span class="fn">John Williams</span> (former editor, <span
					class="company"><a href="http://www.quark.com/">Quark,
						Inc.</a></span>)
			</dd>
		</dl>

		<p>
			Please refer to the <a
				href="http://www.w3.org/Style/2011/REC-css3-selectors-20110929-errata.html"><strong>errata</strong></a>
			for this document, which may include some normative corrections.
		</p>

		<p>
			See also <a
				href="http://www.w3.org/2003/03/Translations/byTechnology?technology=css3-selectors">
				<strong>translations</strong>
			</a>.
		</p>

		<!--begin-copyright-->
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			<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
			© 2011 <a href="http://www.w3.org/"><acronym
				title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a
				href="http://www.csail.mit.edu/"><acronym
				title="Massachusetts Institute of Technology">MIT</acronym></a>, <a
				href="http://www.ercim.eu/"><acronym
				title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>,
			<a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C
			<a
				href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
			<a
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				use</a> rules apply.
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		<!--end-copyright-->
		<hr title="Separator for header">
	</div>

	<h2 class="no-num no-toc" id="abstract">Abstract</h2>

	<p>
		<em>Selectors</em> are patterns that match against elements in a tree,
		and as such form one of several technologies that can be used to
		select nodes in an XML document. Selectors have been optimized for use
		with HTML and XML, and are designed to be usable in
		performance-critical code.

	</p>
	<p>
		<acronym title="Cascading Style Sheets">CSS</acronym> (Cascading Style
		Sheets) is a language for describing the rendering of <acronym
			title="Hypertext Markup Language">HTML</acronym> and <acronym
			title="Extensible Markup Language">XML</acronym> documents on screen,
		on paper, in speech, etc. CSS uses Selectors for binding style
		properties to elements in the document.

	</p>
	<p>
		This document describes the selectors that already exist in <abbr
			title="CSS level 1">CSS1</abbr> <a href="#CSS1" rel="biblioentry">[CSS1]<!--{{CSS1}}--></a>
		and <abbr
			title="CSS level
																																																																																												2">CSS2</abbr>
		<a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>, and
		further introduces new selectors for <abbr title="CSS level 3">CSS3</abbr>
		and other languages that may need them.

	</p>
	<p>Selectors define the following function:</p>
	<pre>expression ∗ element → boolean</pre>

	<p>That is, given an element and a selector, this specification
		defines whether that element matches the selector.</p>
	<p>
		These expressions can also be used, for instance, to select a set of
		elements, or a single element from a set of elements, by evaluating
		the expression across all the elements in a subtree. <acronym
			title="Simple
																																	 Tree Transformation Sheets">STTS</acronym>
		(Simple Tree Transformation Sheets), a language for transforming XML
		trees, uses this mechanism. <a href="#STTS3" rel="biblioentry">[STTS3]<!--{{STTS3}}--></a>

	</p>
	<h2 class="no-num no-toc" id="status">Status of this document</h2>
	<!--begin-status-->

	<p>
		<em>This section describes the status of this document at the
			time of its publication. Other documents may supersede this document.
			A list of current W3C publications and the latest revision of this
			technical report can be found in the <a href="http://www.w3.org/TR/">W3C
				technical reports index at http://www.w3.org/TR/.</a>
		</em>

	</p>
	<p>
		This document was produced by the <a
			href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> as a
		<a href="http://www.w3.org/Consortium/Process/tr#RecsPR">Proposed
			Recommendation.</a>

	</p>
	<p>
		A W3C Recommendation is a mature document that has been widely
		reviewed and has been shown to be implementable. W3C encourages
		everybody to implement this specification. Comments may be sent to the
		(<a href="http://lists.w3.org/Archives/Public/www-style/">archived</a>)
		public mailing list <a
			href="mailto:www-style@w3.org?Subject=%5Bcss3-selectors%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>
		(see <a href="http://www.w3.org/Mail/Request">instructions</a>). When
		sending e-mail, please put the text “css3-selectors” in the subject,
		preferably like this: “[
		<!---->
		css3-selectors
		<!---->
		] <em>…summary of comment…</em>”

	</p>
	<p>This document has been reviewed by W3C Members, by software
		developers, and by other W3C groups and interested parties, and is
		endorsed by the Director as a W3C Recommendation. It is a stable
		document and may be used as reference material or cited from another
		document. W3C's role in making the Recommendation is to draw attention
		to the specification and to promote its widespread deployment. This
		enhances the functionality and interoperability of the Web.</p>

	<p>
		This document was produced by a group operating under the <a
			href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5&nbsp;February
			2004 W3C Patent Policy</a>. W3C maintains a <a
			href="http://www.w3.org/2004/01/pp-impl/32061/status"
			rel="disclosure">public list of any patent disclosures</a> made in
		connection with the deliverables of the group; that page also includes
		instructions for disclosing a patent. An individual who has actual
		knowledge of a patent which the individual believes contains <a
			href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
			Claim(s)</a> must disclose the information in accordance with <a
			href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">
			section&nbsp;6 of the W3C Patent Policy</a>.
	</p>
	<!--end-status-->

	<p>
		A separate <a
			href="/Style/CSS/Test/CSS3/Selectors/20091025/reports/CR-ImpReport.html">
			implementation report</a> contains a test suite and shows several
		implementations of the specification.

	</p>
	<p id="changes">This document is the same as the previous, Proposed
		Recommendation version, except for editorial changes to the front
		matter, and updating of references.</p>
	<h2 class="no-num no-toc" id="contents">Table of Contents</h2>
	<!--begin-toc-->

	<ul class="toc">
		<li><a href="#context"><span class="secno">1. </span>Introduction</a>
			<ul class="toc">
				<li><a href="#dependencies"><span class="secno">1.1.
					</span>Dependencies</a></li>
				<li><a href="#terminology"><span class="secno">1.2.
					</span>Terminology</a></li>
				<li><a href="#changesFromCSS2"><span class="secno">1.3.
					</span>Changes from CSS2</a></li>
			</ul></li>
		<li><a href="#selectors"><span class="secno">2. </span>Selectors</a>

		</li>
		<li><a href="#casesens"><span class="secno">3. </span>Case
				sensitivity</a></li>
		<li><a href="#selector-syntax"><span class="secno">4.
			</span>Selector syntax</a></li>
		<li><a href="#grouping"><span class="secno">5. </span>Groups
				of selectors</a></li>
		<li><a href="#simple-selectors"><span class="secno">6.
			</span>Simple selectors</a>
			<ul class="toc">
				<li><a href="#type-selectors"><span class="secno">6.1.
					</span>Type selector</a>
					<ul class="toc">
						<li><a href="#typenmsp"><span class="secno">6.1.1.
							</span>Type selectors and namespaces</a></li>
					</ul></li>
				<li><a href="#universal-selector"><span class="secno">6.2.
					</span>Universal selector </a>
					<ul class="toc">
						<li><a href="#univnmsp"><span class="secno">6.2.1.
							</span>Universal selector and namespaces</a></li>
					</ul></li>
				<li><a href="#attribute-selectors"><span class="secno">6.3.
					</span>Attribute selectors</a>
					<ul class="toc">
						<li><a href="#attribute-representation"><span
								class="secno">6.3.1. </span>Attribute presence and value
								selectors</a></li>
						<li><a href="#attribute-substrings"><span class="secno">6.3.2.
							</span>Substring matching attribute selectors</a></li>
						<li><a href="#attrnmsp"><span class="secno">6.3.3.
							</span>Attribute selectors and namespaces</a></li>
						<li><a href="#def-values"><span class="secno">6.3.4.
							</span>Default attribute values in DTDs</a></li>
					</ul></li>
				<li><a href="#class-html"><span class="secno">6.4. </span>Class
						selectors</a></li>
				<li><a href="#id-selectors"><span class="secno">6.5.
					</span>ID selectors</a></li>
				<li><a href="#pseudo-classes"><span class="secno">6.6.
					</span>Pseudo-classes</a>
					<ul class="toc">
						<li><a href="#dynamic-pseudos"><span class="secno">6.6.1.
							</span>Dynamic pseudo-classes</a>
							<ul class="toc">
								<li><a href="#the-link-pseudo-classes-link-and-visited"><span
										class="secno">6.6.1.1. </span>The link pseudo-classes: :link
										and :visited</a></li>
								<li><a href="#the-user-action-pseudo-classes-hover-act"><span
										class="secno">6.6.1.2. </span>The user action pseudo-classes
										:hover, :active, and :focus</a></li>
							</ul></li>
						<li><a href="#target-pseudo"><span class="secno">6.6.2.
							</span>The target pseudo-class :target</a></li>
						<li><a href="#lang-pseudo"><span class="secno">6.6.3.
							</span>The language pseudo-class :lang</a></li>
						<li><a href="#UIstates"><span class="secno">6.6.4.
							</span>The UI element states pseudo-classes</a>
							<ul class="toc">
								<li><a href="#enableddisabled"><span class="secno">6.6.4.1.
									</span>The :enabled and :disabled pseudo-classes</a></li>
								<li><a href="#checked"><span class="secno">6.6.4.2.
									</span>The :checked pseudo-class</a></li>
								<li><a href="#indeterminate"><span class="secno">6.6.4.3.
									</span>The :indeterminate pseudo-class</a></li>
							</ul></li>
						<li><a href="#structural-pseudos"><span class="secno">6.6.5.
							</span>Structural pseudo-classes</a>
							<ul class="toc">
								<li><a href="#root-pseudo"><span class="secno">6.6.5.1.
									</span>:root pseudo-class</a></li>
								<li><a href="#nth-child-pseudo"><span class="secno">6.6.5.2.
									</span>:nth-child() pseudo-class</a></li>
								<li><a href="#nth-last-child-pseudo"><span
										class="secno">6.6.5.3. </span>:nth-last-child() pseudo-class</a></li>
								<li><a href="#nth-of-type-pseudo"><span class="secno">6.6.5.4.
									</span>:nth-of-type() pseudo-class</a></li>
								<li><a href="#nth-last-of-type-pseudo"><span
										class="secno">6.6.5.5. </span>:nth-last-of-type() pseudo-class</a>

								</li>
								<li><a href="#first-child-pseudo"><span class="secno">6.6.5.6.
									</span>:first-child pseudo-class</a></li>
								<li><a href="#last-child-pseudo"><span class="secno">6.6.5.7.
									</span>:last-child pseudo-class</a></li>
								<li><a href="#first-of-type-pseudo"><span class="secno">6.6.5.8.
									</span>:first-of-type pseudo-class</a></li>
								<li><a href="#last-of-type-pseudo"><span class="secno">6.6.5.9.
									</span>:last-of-type pseudo-class</a></li>
								<li><a href="#only-child-pseudo"><span class="secno">6.6.5.10.
									</span>:only-child pseudo-class</a></li>
								<li><a href="#only-of-type-pseudo"><span class="secno">6.6.5.11.
									</span>:only-of-type pseudo-class</a></li>
								<li><a href="#empty-pseudo"><span class="secno">6.6.5.12.
									</span>:empty pseudo-class</a></li>
							</ul></li>
						<li><a href="#content-selectors"><span class="secno">6.6.6.
							</span>Blank</a></li>
						<li><a href="#negation"><span class="secno">6.6.7.
							</span>The negation pseudo-class</a></li>
					</ul></li>
			</ul></li>
		<li><a href="#pseudo-elements"><span class="secno">7.
			</span>Pseudo-elements</a>
			<ul class="toc">
				<li><a href="#first-line"><span class="secno">7.1. </span>The
						::first-line pseudo-element</a>
					<ul class="toc">
						<li><a href="#first-formatted-line"><span class="secno">7.1.1.
							</span>First formatted line definition in CSS</a></li>
					</ul></li>
				<li><a href="#first-letter"><span class="secno">7.2.
					</span>The ::first-letter pseudo-element</a>
					<ul class="toc">
						<li><a href="#application-in-css"><span class="secno">7.2.1.
							</span>Application in CSS</a></li>
					</ul></li>
				<li><a href="#selection"><span class="secno">7.3. </span>Blank</a>

				</li>
				<li><a href="#gen-content"><span class="secno">7.4.
					</span>The ::before and ::after pseudo-elements</a></li>
			</ul></li>
		<li><a href="#combinators"><span class="secno">8. </span>Combinators</a>
			<ul class="toc">
				<li><a href="#descendant-combinators"><span class="secno">8.1.
					</span>Descendant combinator</a></li>
				<li><a href="#child-combinators"><span class="secno">8.2.
					</span>Child combinators</a></li>
				<li><a href="#sibling-combinators"><span class="secno">8.3.
					</span>Sibling combinators</a>
					<ul class="toc">
						<li><a href="#adjacent-sibling-combinators"><span
								class="secno">8.3.1. </span>Adjacent sibling combinator</a></li>
						<li><a href="#general-sibling-combinators"><span
								class="secno">8.3.2. </span>General sibling combinator</a></li>
					</ul></li>
			</ul></li>
		<li><a href="#specificity"><span class="secno">9. </span>Calculating
				a selector's specificity</a></li>
		<li><a href="#w3cselgrammar"><span class="secno">10. </span>The
				grammar of Selectors</a>
			<ul class="toc">
				<li><a href="#grammar"><span class="secno">10.1. </span>Grammar</a>

				</li>
				<li><a href="#lex"><span class="secno">10.2. </span>Lexical
						scanner</a></li>
			</ul></li>
		<li><a href="#profiling"><span class="secno">11. </span>Profiles</a>

		</li>
		<li><a href="#Conformance"><span class="secno">12. </span>Conformance
				and requirements</a></li>
		<li><a href="#Tests"><span class="secno">13. </span>Tests</a></li>
		<li><a href="#ACKS"><span class="secno">14. </span>Acknowledgements</a>

		</li>
		<li><a href="#references"><span class="secno">15. </span>References</a>
			<ul class="toc">
				<li><a href="#normative-references"><span class="secno">15.1.
					</span>Normative References</a></li>
				<li><a href="#informative-references"><span class="secno">15.2.
					</span>Informative References</a></li>
			</ul></li>
	</ul>
	<!--end-toc-->

	<h2 id="context">
		<span class="secno">1. </span>Introduction
	</h2>

	<p>
		Selectors Level 1 and Selectors Level 2 are defined as the subsets of
		selector functionality defined in the <a
			href="http://www.w3.org/TR/REC-CSS1">CSS1</a> and <a
			href="http://www.w3.org/TR/CSS21/">CSS2.1</a> specifications,
		respectively.

	</p>
	<h3 id="dependencies">
		<span class="secno">1.1. </span>Dependencies
	</h3>

	<p>
		Some features of this specification are specific to CSS, or have
		particular limitations or rules specific to CSS. In this
		specification, these have been described in terms of CSS2.1. <a
			href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>

	</p>
	<h3 id="terminology">
		<span class="secno">1.2. </span>Terminology
	</h3>

	<p>All of the text of this specification is normative except
		examples, notes, and sections explicitly marked as non-normative.</p>
	<p>
		Additional terminology is defined in the <a
			href="http://www.w3.org/TR/CSS21/conform.html#defs">Definitions</a>
		section of <a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>.
		Examples of document source code and fragments are given in XML
		[[XML10] or HTML [[HTML40]] syntax.

	</p>
	<h3 id="changesFromCSS2">
		<span class="secno">1.3. </span>Changes from CSS2
	</h3>

	<p>
		<em>This section is non-normative.</em>

	</p>
	<p>The main differences between the selectors in CSS2 and those in
		Selectors are:</p>
	<ul>
		<li>the list of basic definitions (selector, group of selectors,
			simple selector, etc.) has been changed; in particular, what was
			referred to in CSS2 as a simple selector is now called a sequence of
			simple selectors, and the term "simple selector" is now used for the
			components of this sequence</li>
		<li>an optional namespace component is now allowed in element
			type selectors, the universal selector and attribute selectors</li>
		<li>a <a href="#general-sibling-combinators">new combinator</a>
			has been introduced

		</li>
		<li>new simple selectors including substring matching attribute
			selectors, and new pseudo-classes</li>
		<li>new pseudo-elements, and introduction of the "::" convention
			for pseudo-elements</li>
		<li>the grammar has been rewritten</li>
		<li>profiles to be added to specifications integrating Selectors
			and defining the set of selectors which is actually supported by each
			specification</li>
		<li>Selectors are now a CSS3 Module and an independent
			specification; other specifications can now refer to this document
			independently of CSS</li>
		<li>the specification now has its own test suite</li>
	</ul>

	<h2 id="selectors">
		<span class="secno">2. </span>Selectors
	</h2>

	<p>
		<em>This section is non-normative, as it merely summarizes the
			following sections.</em>

	</p>
	<p>A Selector represents a structure. This structure can be used as
		a condition (e.g. in a CSS rule) that determines which elements a
		selector matches in the document tree, or as a flat description of the
		HTML or XML fragment corresponding to that structure.</p>
	<p>Selectors may range from simple element names to rich contextual
		representations.</p>
	<p>The following table summarizes the Selector syntax:</p>
	<table class="selectorsReview">
		<thead>
			<tr>
				<th class="pattern">Pattern</th>
				<th class="meaning">Meaning</th>
				<th class="described">Described in section</th>
				<th class="origin">First defined in CSS level</th>
			</tr>
		</thead>
		<tbody>
			<tr>
				<td class="pattern">*</td>
				<td class="meaning">any element</td>
				<td class="described"><a href="#universal-selector">Universal
						selector</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E</td>
				<td class="meaning">an element of type E</td>
				<td class="described"><a href="#type-selectors">Type
						selector</a></td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E[foo]</td>
				<td class="meaning">an E element with a "foo" attribute</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E[foo="bar"]</td>
				<td class="meaning">an E element whose "foo" attribute value is
					exactly equal to "bar"</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E[foo~="bar"]</td>
				<td class="meaning">an E element whose "foo" attribute value is
					a list of whitespace-separated values, one of which is exactly
					equal to "bar"</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E[foo^="bar"]</td>
				<td class="meaning">an E element whose "foo" attribute value
					begins exactly with the string "bar"</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E[foo$="bar"]</td>
				<td class="meaning">an E element whose "foo" attribute value
					ends exactly with the string "bar"</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E[foo*="bar"]</td>
				<td class="meaning">an E element whose "foo" attribute value
					contains the substring "bar"</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E[foo|="en"]</td>
				<td class="meaning">an E element whose "foo" attribute has a
					hyphen-separated list of values beginning (from the left) with "en"

				</td>
				<td class="described"><a href="#attribute-selectors">Attribute
						selectors</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E:root</td>
				<td class="meaning">an E element, root of the document</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:nth-child(n)</td>
				<td class="meaning">an E element, the n-th child of its parent

				</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:nth-last-child(n)</td>
				<td class="meaning">an E element, the n-th child of its parent,
					counting from the last one</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:nth-of-type(n)</td>
				<td class="meaning">an E element, the n-th sibling of its type

				</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:nth-last-of-type(n)</td>
				<td class="meaning">an E element, the n-th sibling of its type,
					counting from the last one</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:first-child</td>
				<td class="meaning">an E element, first child of its parent</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E:last-child</td>
				<td class="meaning">an E element, last child of its parent</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:first-of-type</td>
				<td class="meaning">an E element, first sibling of its type</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:last-of-type</td>
				<td class="meaning">an E element, last sibling of its type</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:only-child</td>
				<td class="meaning">an E element, only child of its parent</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:only-of-type</td>
				<td class="meaning">an E element, only sibling of its type</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:empty</td>
				<td class="meaning">an E element that has no children
					(including text nodes)</td>
				<td class="described"><a href="#structural-pseudos">Structural
						pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:link<br> E:visited

				</td>
				<td class="meaning">an E element being the source anchor of a
					hyperlink of which the target is not yet visited (:link) or already
					visited (:visited)</td>
				<td class="described"><a href="#link">The link
						pseudo-classes</a></td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E:active<br> E:hover<br> E:focus

				</td>
				<td class="meaning">an E element during certain user actions</td>
				<td class="described"><a href="#useraction-pseudos">The
						user action pseudo-classes</a></td>
				<td class="origin">1 and 2</td>
			</tr>
			<tr>
				<td class="pattern">E:target</td>
				<td class="meaning">an E element being the target of the
					referring URI</td>
				<td class="described"><a href="#target-pseudo">The target
						pseudo-class</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:lang(fr)</td>
				<td class="meaning">an element of type E in language "fr" (the
					document language specifies how language is determined)</td>
				<td class="described"><a href="#lang-pseudo">The :lang()
						pseudo-class</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E:enabled<br> E:disabled

				</td>
				<td class="meaning">a user interface element E which is enabled
					or disabled</td>
				<td class="described"><a href="#UIstates">The UI element
						states pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E:checked<!--<br>E:indeterminate-->

				</td>
				<td class="meaning">a user interface element E which is checked<!-- or in an
											indeterminate state--> (for instance a radio-button or
					checkbox)

				</td>
				<td class="described"><a href="#UIstates">The UI element
						states pseudo-classes</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E::first-line</td>
				<td class="meaning">the first formatted line of an E element</td>
				<td class="described"><a href="#first-line">The
						::first-line pseudo-element</a></td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E::first-letter</td>
				<td class="meaning">the first formatted letter of an E element

				</td>
				<td class="described"><a href="#first-letter">The
						::first-letter pseudo-element</a></td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E::before</td>
				<td class="meaning">generated content before an E element</td>
				<td class="described"><a href="#gen-content">The ::before
						pseudo-element</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E::after</td>
				<td class="meaning">generated content after an E element</td>
				<td class="described"><a href="#gen-content">The ::after
						pseudo-element</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E.warning</td>
				<td class="meaning">an E element whose class is "warning" (the
					document language specifies how class is determined).</td>
				<td class="described"><a href="#class-html">Class selectors</a>

				</td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E#myid</td>
				<td class="meaning">an E element with ID equal to "myid".</td>
				<td class="described"><a href="#id-selectors">ID selectors</a>

				</td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E:not(s)</td>
				<td class="meaning">an E element that does not match simple
					selector s</td>
				<td class="described"><a href="#negation">Negation
						pseudo-class</a></td>
				<td class="origin">3</td>
			</tr>
			<tr>
				<td class="pattern">E F</td>
				<td class="meaning">an F element descendant of an E element</td>
				<td class="described"><a href="#descendant-combinators">Descendant
						combinator</a></td>
				<td class="origin">1</td>
			</tr>
			<tr>
				<td class="pattern">E &gt; F</td>
				<td class="meaning">an F element child of an E element</td>
				<td class="described"><a href="#child-combinators">Child
						combinator</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E + F</td>
				<td class="meaning">an F element immediately preceded by an E
					element</td>
				<td class="described"><a href="#adjacent-sibling-combinators">Adjacent
						sibling combinator</a></td>
				<td class="origin">2</td>
			</tr>
			<tr>
				<td class="pattern">E ~ F</td>
				<td class="meaning">an F element preceded by an E element</td>
				<td class="described"><a href="#general-sibling-combinators">General
						sibling combinator</a></td>
				<td class="origin">3</td>
			</tr>
		</tbody>
	</table>

	<p>The meaning of each selector is derived from the table above by
		prepending "matches" to the contents of each cell in the "Meaning"
		column.</p>
	<h2 id="casesens">
		<span class="secno">3. </span>Case sensitivity
	</h2>

	<p>
		All Selectors syntax is case-insensitive within the ASCII range (i.e.
		[a-z] and [A-Z] are equivalent), except for parts that are not under
		the control of Selectors. The case sensitivity of document language
		element names, attribute names, and attribute values in selectors
		depends on the document language. For example, in HTML, element names
		are case-insensitive, but in XML, they are case-sensitive. Case
		sensitivity of namespace prefixes is defined in <a
			href="#CSS3NAMESPACE" rel="biblioentry">[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>.

	</p>
	<h2 id="selector-syntax">
		<span class="secno">4. </span>Selector syntax
	</h2>

	<p>
		A
		<dfn id="selector">selector</dfn>
		is a chain of one or more <a href="#sequence">sequences of simple
			selectors</a> separated by <a href="#combinators">combinators</a>. One <a
			href="#pseudo-elements">pseudo-element</a> may be appended to the
		last sequence of simple selectors in a selector.

	</p>
	<p>
		A
		<dfn id="sequence-of-simple-selectors">
			<a name="sequence">sequence of simple selectors</a>
		</dfn>
		is a chain of <a href="#simple-selectors-dfn">simple selectors</a>
		that are not separated by a <a href="#combinators">combinator</a>. It
		always begins with a <a href="#type-selectors">type selector</a> or a
		<a href="#universal-selector">universal selector</a>. No other type
		selector or universal selector is allowed in the sequence.

	</p>
	<p>
		A
		<dfn id="simple-selector">
			<a name="simple-selectors-dfn"></a><a href="#simple-selectors">simple
				selector</a>
		</dfn>
		is either a <a href="#type-selectors">type selector</a>, <a
			href="#universal-selector">universal selector</a>, <a
			href="#attribute-selectors">attribute selector</a>, <a
			href="#class-html">class selector</a>, <a href="#id-selectors">ID
			selector</a>, or <a href="#pseudo-classes">pseudo-class</a>.

	</p>
	<p>
		<dfn id="combinators0">Combinators</dfn>
		are: whitespace, "greater-than sign" (U+003E,
		<code>&gt;</code>
		), "plus sign" (U+002B,
		<code>+</code>
		) and "tilde" (U+007E,
		<code>~</code>
		). White space may appear between a combinator and the simple
		selectors around it. <a name="whitespace"></a>Only the characters
		"space" (U+0020), "tab" (U+0009), "line feed" (U+000A), "carriage
		return" (U+000D), and "form feed" (U+000C) can occur in whitespace.
		Other space-like characters, such as "em-space" (U+2003) and
		"ideographic space" (U+3000), are never part of whitespace.

	</p>
	<p>
		The elements of a document tree that are represented by a selector are
		the
		<dfn id="subjects-of-the-selector">
			<a name="subject"></a>subjects of the selector
		</dfn>
		. A selector consisting of a single sequence of simple selectors
		represents any element satisfying its requirements. Prepending another
		sequence of simple selectors and a combinator to a sequence imposes
		additional matching constraints, so the subjects of a selector are
		always a subset of the elements represented by the last sequence of
		simple selectors.

	</p>
	<p>
		An empty selector, containing no sequence of simple selectors and no
		pseudo-element, is an <a href="#Conformance">invalid selector</a>.

	</p>
	<p>
		Characters in Selectors can be escaped with a backslash according to
		the same <a href="http://www.w3.org/TR/CSS21/syndata.html#characters">escaping
			rules</a> as CSS. <a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>.

	</p>
	<p id="nsdecl">
		Certain selectors support namespace prefixes. The mechanism by which
		namespace prefixes are
		<dfn id="declared">declared</dfn>
		should be specified by the language that uses Selectors. If the
		language does not specify a namespace prefix declaration mechanism,
		then no prefixes are declared. In CSS, namespace prefixes are declared
		with the <a href="http://www.w3.org/TR/css3-namespace/#declaration"><code>@namespace</code></a>
		rule. <a href="#CSS3NAMESPACE" rel="biblioentry">[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>

	</p>
	<h2 id="grouping">
		<span class="secno">5. </span>Groups of selectors
	</h2>

	<p>A comma-separated list of selectors represents the union of all
		elements selected by each of the individual selectors in the list. (A
		comma is U+002C.) For example, in CSS when several selectors share the
		same declarations, they may be grouped into a comma-separated list.
		White space may appear before and/or after the comma.</p>
	<div class="example">
		<p>CSS example:</p>

		<p>In this example, we condense three rules with identical
			declarations into one. Thus,</p>

		<pre>h1 { font-family: sans-serif }
			h2 { font-family: sans-serif }
			h3 { font-family: sans-serif }</pre>

		<p>is equivalent to:</p>

		<pre>h1, h2, h3 { font-family: sans-serif }</pre>
	</div>

	<p>
		<strong>Warning</strong>: the equivalence is true in this example
		because all the selectors are valid selectors. If just one of these
		selectors were invalid, the entire group of selectors would be
		invalid. This would invalidate the rule for all three heading
		elements, whereas in the former case only one of the three individual
		heading rules would be invalidated.

	</p>
	<div class="example">
		<p>Invalid CSS example:</p>

		<pre>h1 { font-family: sans-serif }
			h2..foo { font-family: sans-serif }
			h3 { font-family: sans-serif }</pre>

		<p>is not equivalent to:</p>

		<pre>h1, h2..foo, h3 { font-family: sans-serif }</pre>

		<p>
			because the above selector (
			<code>h1, h2..foo, h3</code>
			) is entirely invalid and the entire style rule is dropped. (When the
			selectors are not grouped, only the rule for
			<code>h2..foo</code>
			is dropped.)
		</p>
	</div>

	<h2 id="simple-selectors">
		<span class="secno">6. </span>Simple selectors
	</h2>

	<h3 id="type-selectors">
		<span class="secno">6.1. </span>Type selector
	</h3>

	<p>
		A
		<dfn id="type-selector">type selector</dfn>
		is the name of a document language element type written using the
		syntax of <a href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS
			qualified names</a> <a href="#CSS3NAMESPACE" rel="biblioentry">[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>.
		A type selector represents an instance of the element type in the
		document tree.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			The following selector represents an
			<code>h1</code>
			element in the document tree:
		</p>

		<pre>h1</pre>
	</div>

	<h4 id="typenmsp">
		<span class="secno">6.1.1. </span>Type selectors and namespaces
	</h4>

	<p>
		Type selectors allow an optional namespace component: a namespace
		prefix that has been previously <a href="#nsdecl">declared</a> may be
		prepended to the element name separated by the namespace separator
		"vertical bar" (U+007C,
		<code>|</code>
		). (See, e.g., <a href="#XML-NAMES" rel="biblioentry">[XML-NAMES]<!--{{XML-NAMES}}--></a>
		for the use of namespaces in XML.)

	</p>
	<p>The namespace component may be left empty (no prefix before the
		namespace separator) to indicate that the selector is only to
		represent elements with no namespace.</p>
	<p>An asterisk may be used for the namespace prefix, indicating
		that the selector represents elements in any namespace (including
		elements with no namespace).</p>
	<p>
		Element type selectors that have no namespace component (no namespace
		separator) represent elements without regard to the element's
		namespace (equivalent to "
		<code>*|</code>
		") unless a default namespace has been <a href="#nsdecl">declared</a>
		for namespaced selectors (e.g. in CSS, in the style sheet). If a
		default namespace has been declared, such selectors will represent
		only elements in the default namespace.

	</p>
	<p>
		A type selector containing a namespace prefix that has not been
		previously <a href="#nsdecl">declared</a> for namespaced selectors is
		an <a href="#Conformance">invalid</a> selector.

	</p>
	<p>
		In a namespace-aware client, the name part of element type selectors
		(the part after the namespace separator, if it is present) will only
		match against the <a
			href="http://www.w3.org/TR/REC-xml-names/#NT-LocalPart">local
			part</a> of the element's <a
			href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">qualified
			name</a>.

	</p>
	<p>In summary:</p>
	<dl>
		<dt>
			<code>ns|E</code>

		</dt>
		<dd>elements with name E in namespace ns</dd>
		<dt>
			<code>*|E</code>

		</dt>
		<dd>elements with name E in any namespace, including those
			without a namespace</dd>
		<dt>
			<code>|E</code>

		</dt>
		<dd>elements with name E without a namespace</dd>
		<dt>
			<code>E</code>

		</dt>
		<dd>
			if no default namespace has been <a href="#nsdecl">declared</a> for
			selectors, this is equivalent to *|E. Otherwise it is equivalent to
			ns|E where ns is the default namespace.
		</dd>
	</dl>

	<div class="example">
		<p>CSS examples:</p>

		<pre>@namespace foo url(http://www.example.com);
			foo|h1 { color: blue }  /* first rule */
			foo|* { color: yellow } /* second rule */
			|h1 { color: red }      /* ...*/
			*|h1 { color: green }
			h1 { color: green }</pre>

		<p>
			The first rule (not counting the
			<code>@namespace</code>
			at-rule) will match only
			<code>h1</code>
			elements in the "http://www.example.com" namespace.
		</p>

		<p>The second rule will match all elements in the
			"http://www.example.com" namespace.</p>

		<p>
			The third rule will match only
			<code>h1</code>
			elements with no namespace.
		</p>

		<p>
			The fourth rule will match
			<code>h1</code>
			elements in any namespace (including those without any namespace).
		</p>

		<p>The last rule is equivalent to the fourth rule because no
			default namespace has been defined.</p>
	</div>

	<h3 id="universal-selector">
		<span class="secno">6.2. </span>Universal selector
	</h3>

	<p>
		The
		<dfn id="universal-selector0">universal selector</dfn>
		, written as a <a
			href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS
			qualified name</a> <a href="#CSS3NAMESPACE" rel="biblioentry">[CSS3NAMESPACE]<!--{{!CSS3NAMESPACE}}--></a>
		with an asterisk (
		<code>*</code>
		U+002A) as the local name, represents the qualified name of any
		element type. It represents any single element in the document tree in
		any namespace (including those without a namespace) if no default
		namespace has been specified for selectors. If a default namespace has
		been specified, see <a href="#univnmsp">Universal selector and
			Namespaces</a> below.

	</p>
	<p>
		If a universal selector represented by
		<code>*</code>
		(i.e. without a namespace prefix) is not the only component of a <a
			href="#sequence">sequence of simple selectors</a> selectors or is
		immediately followed by a <a href="#pseudo-elements">pseudo-element</a>,
		then the
		<code>*</code>
		may be omitted and the universal selector's presence implied.

	</p>
	<div class="example">
		<p>Examples:</p>

		<ul>
			<li><code>*[hreflang|=en]</code> and <code>[hreflang|=en]</code>
				are equivalent,</li>
			<li><code>*.warning</code> and <code>.warning</code> are
				equivalent,</li>
			<li><code>*#myid</code> and <code>#myid</code> are equivalent.</li>
		</ul>
	</div>

	<p class="note">
		<strong>Note:</strong> it is recommended that the
		<code>*</code>
		not be omitted, because it decreases the potential confusion between,
		for example,
		<code style="white-space: nowrap">div :first-child</code>
		and
		<code style="white-space: nowrap">div:first-child</code>
		. Here,
		<code style="white-space: nowrap">div *:first-child</code>
		is more readable.

	</p>
	<h4 id="univnmsp">
		<span class="secno">6.2.1. </span>Universal selector and namespaces
	</h4>

	<p>The universal selector allows an optional namespace component.
		It is used as follows:</p>
	<dl>
		<dt>
			<code>ns|*</code>

		</dt>
		<dd>all elements in namespace ns</dd>
		<dt>
			<code>*|*</code>

		</dt>
		<dd>all elements</dd>
		<dt>
			<code>|*</code>

		</dt>
		<dd>all elements without a namespace</dd>
		<dt>
			<code>*</code>

		</dt>
		<dd>if no default namespace has been specified, this is
			equivalent to *|*. Otherwise it is equivalent to ns|* where ns is the
			default namespace.</dd>
	</dl>

	<p>
		A universal selector containing a namespace prefix that has not been
		previously <a href="#nsdecl">declared</a> is an <a href="#Conformance">invalid</a>
		selector.

	</p>
	<h3 id="attribute-selectors">
		<span class="secno">6.3. </span>Attribute selectors
	</h3>

	<p>Selectors allow the representation of an element's attributes.
		When a selector is used as an expression to match against an element,
		attribute selectors must be considered to match an element if that
		element has an attribute that matches the attribute represented by the
		attribute selector.</p>
	<h4 id="attribute-representation">
		<span class="secno">6.3.1. </span>Attribute presence and value
		selectors
	</h4>

	<p>CSS2 introduced four attribute selectors:</p>
	<dl>
		<dt>
			<code>[att]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute, whatever the value of the attribute.

		</dd>
		<dt>
			<code>[att=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute whose value is exactly "val".

		</dd>
		<dt>
			<code>[att~=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute whose value is a <a href="#whitespace">whitespace</a>-separated
			list of words, one of which is exactly "val". If "val" contains
			whitespace, it will never represent anything (since the words are <em>separated</em>
			by spaces). Also if "val" is the empty string, it will never
			represent anything.

		</dd>
		<dt>
			<code>[att|=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute, its value either being exactly "val" or beginning with
			"val" immediately followed by "-" (U+002D). This is primarily
			intended to allow language subcode matches (e.g., the
			<code>hreflang</code>
			attribute on the
			<code>a</code>
			element in HTML) as described in BCP 47 (<a href="#BCP47"
				rel="biblioentry">[BCP47]<!--{{BCP47}}--></a>) or its successor. For
			<code>lang</code>
			(or
			<code>xml:lang</code>
			) language subcode matching, please see <a href="#lang-pseudo">the
				<code>:lang</code> pseudo-class
			</a>.
		</dd>
	</dl>

	<p>
		Attribute values must be CSS <a
			href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>
		or <a href="http://www.w3.org/TR/CSS21/syndata.html#strings">strings</a>.
		<a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a> The
		case-sensitivity of attribute names and values in selectors depends on
		the document language.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following attribute selector represents an
			<code>h1</code>
			element that carries the
			<code>title</code>
			attribute, whatever its value:
		</p>

		<pre>h1[title]</pre>

		<p>
			In the following example, the selector represents a
			<code>span</code>
			element whose
			<code>class</code>
			attribute has exactly the value "example":
		</p>

		<pre>span[class="example"]</pre>

		<p>
			Multiple attribute selectors can be used to represent several
			attributes of an element, or several conditions on the same
			attribute. Here, the selector represents a
			<code>span</code>
			element whose
			<code>hello</code>
			attribute has exactly the value "Cleveland" and whose
			<code>goodbye</code>
			attribute has exactly the value "Columbus":
		</p>

		<pre>span[hello="Cleveland"][goodbye="Columbus"]</pre>

		<p>
			The following CSS rules illustrate the differences between "=" and
			"~=". The first selector would match, for example, an
			<code>a</code>
			element with the value "copyright copyleft copyeditor" on a
			<code>rel</code>
			attribute. The second selector would only match an
			<code>a</code>
			element with an
			<code>href</code>
			attribute having the exact value "http://www.w3.org/".
		</p>

		<pre>a[rel~="copyright"] { ... }
			a[href="http://www.w3.org/"] { ... }</pre>

		<p>
			The following selector represents an
			<code>a</code>
			element whose
			<code>hreflang</code>
			attribute is exactly "fr".
		</p>

		<pre>a[hreflang=fr]</pre>

		<p>
			The following selector represents an
			<code>a</code>
			element for which the value of the
			<code>hreflang</code>
			attribute begins with "en", including "en", "en-US", and "en-scouse":
		</p>

		<pre>a[hreflang|="en"]</pre>

		<p>
			The following selectors represent a
			<code>DIALOGUE</code>
			element whenever it has one of two different values for an attribute
			<code>character</code>
			:
		</p>

		<pre>DIALOGUE[character=romeo]
			DIALOGUE[character=juliet]</pre>
	</div>

	<h4 id="attribute-substrings">
		<span class="secno">6.3.2. </span>Substring matching attribute
		selectors
	</h4>

	<p>Three additional attribute selectors are provided for matching
		substrings in the value of an attribute:</p>
	<dl>
		<dt>
			<code>[att^=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute whose value begins with the prefix "val". If "val" is the
			empty string then the selector does not represent anything.

		</dd>
		<dt>
			<code>[att$=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute whose value ends with the suffix "val". If "val" is the
			empty string then the selector does not represent anything.

		</dd>
		<dt>
			<code>[att*=val]</code>

		</dt>
		<dd>
			Represents an element with the
			<code>att</code>
			attribute whose value contains at least one instance of the substring
			"val". If "val" is the empty string then the selector does not
			represent anything.
		</dd>
	</dl>

	<p>
		Attribute values must be CSS <a
			href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>
		or <a href="http://www.w3.org/TR/CSS21/syndata.html#strings">strings</a>.
		<a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a> The
		case-sensitivity of attribute names in selectors depends on the
		document language.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following selector represents an HTML
			<code>object</code>
			, referencing an image:
		</p>

		<pre>object[type^="image/"]</pre>

		<p>
			The following selector represents an HTML anchor
			<code>a</code>
			with an
			<code>href</code>
			attribute whose value ends with ".html".
		</p>

		<pre>a[href$=".html"]</pre>

		<p>
			The following selector represents an HTML paragraph with a
			<code>title</code>
			attribute whose value contains the substring "hello"
		</p>

		<pre>p[title*="hello"]</pre>
	</div>

	<h4 id="attrnmsp">
		<span class="secno">6.3.3. </span>Attribute selectors and namespaces
	</h4>

	<p>
		The attribute name in an attribute selector is given as a <a
			href="http://www.w3.org/TR/css3-namespace/#css-qnames">CSS
			qualified name</a>: a namespace prefix that has been previously <a
			href="#nsdecl">declared</a> may be prepended to the attribute name
		separated by the namespace separator "vertical bar" (
		<code>|</code>
		). In keeping with the Namespaces in the XML recommendation, default
		namespaces do not apply to attributes, therefore attribute selectors
		without a namespace component apply only to attributes that have no
		namespace (equivalent to "
		<code>|attr</code>
		"; these attributes are said to be in the "per-element-type namespace
		partition"). An asterisk may be used for the namespace prefix
		indicating that the selector is to match all attribute names without
		regard to the attribute's namespace.

	</p>
	<p>
		An attribute selector with an attribute name containing a namespace
		prefix that has not been previously <a href="#nsdecl">declared</a> is
		an <a href="#Conformance">invalid</a> selector.

	</p>
	<div class="example">
		<p>CSS examples:</p>

		<pre>@namespace foo "http://www.example.com";
			[foo|att=val] { color: blue }
			[*|att] { color: yellow }
			[|att] { color: green }
			[att] { color: green }</pre>

		<p>
			The first rule will match only elements with the attribute
			<code>att</code>
			in the "http://www.example.com" namespace with the value "val".
		</p>

		<p>
			The second rule will match only elements with the attribute
			<code>att</code>
			regardless of the namespace of the attribute (including no
			namespace).
		</p>

		<p>
			The last two rules are equivalent and will match only elements with
			the attribute
			<code>att</code>
			where the attribute is not in a namespace.
		</p>
	</div>

	<h4 id="def-values">
		<span class="secno">6.3.4. </span>Default attribute values in DTDs
	</h4>

	<p>Attribute selectors represent attribute values in the document
		tree. How that document tree is constructed is outside the scope of
		Selectors. In some document formats default attribute values can be
		defined in a DTD or elsewhere, but these can only be selected by
		attribute selectors if they appear in the document tree. Selectors
		should be designed so that they work whether or not the default values
		are included in the document tree.</p>
	<p>
		For example, a XML UA may, but is <em>not</em> required to read an
		"external subset" of the DTD but <em>is</em> required to look for
		default attribute values in the document's "internal subset." (See,
		e.g., <a href="#XML10" rel="biblioentry">[XML10]<!--{{XML10}}--></a>
		for definitions of these subsets.) Depending on the UA, a default
		attribute value defined in the external subset of the DTD might or
		might not appear in the document tree.

	</p>
	<p>
		A UA that recognizes an XML namespace may, but is not required to use
		its knowledge of that namespace to treat default attribute values as
		if they were present in the document. (For example, an XHTML UA is not
		required to use its built-in knowledge of the XHTML DTD. See, e.g., <a
			href="#XML-NAMES" rel="biblioentry">[XML-NAMES]<!--{{XML-NAMES}}--></a>
		for details on namespaces in XML 1.0.)

	</p>
	<p class="note">
		<strong>Note:</strong> Typically, implementations choose to ignore
		external subsets. This corresponds to the behaviour of non-validating
		processors as defined by the XML specification.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			Consider an element
			<code>EXAMPLE</code>
			with an attribute
			<code>radix</code>
			that has a default value of
			<code>"decimal"</code>
			. The DTD fragment might be
		</p>

		<pre class="dtd-example">&lt;!ATTLIST EXAMPLE radix (decimal,octal) "decimal"&gt;</pre>

		<p>If the style sheet contains the rules</p>

		<pre>EXAMPLE[radix=decimal] { /*... default property settings ...*/ }
			EXAMPLE[radix=octal]   { /*... other settings...*/ }</pre>

		<p>
			the first rule might not match elements whose
			<code>radix</code>
			attribute is set by default, i.e. not set explicitly. To catch all
			cases, the attribute selector for the default value must be dropped:
		</p>

		<pre>EXAMPLE                { /*... default property settings ...*/ }
			EXAMPLE[radix=octal]   { /*... other settings...*/ }</pre>

		<p>
			Here, because the selector
			<code>EXAMPLE[radix=octal]</code>
			is more specific than the type selector alone, the style declarations
			in the second rule will override those in the first for elements that
			have a
			<code>radix</code>
			attribute value of
			<code>"octal"</code>
			. Care has to be taken that all property declarations that are to
			apply only to the default case are overridden in the non-default
			cases' style rules.
		</p>
	</div>

	<h3 id="class-html">
		<span class="secno">6.4. </span>Class selectors
	</h3>

	<p>
		Working with HTML, authors may use the "period" notation (also known
		as "full stop", U+002E,
		<code>.</code>
		) as an alternative to the
		<code>~=</code>
		notation when representing the
		<code>class</code>
		attribute. Thus, for HTML,
		<code>div.value</code>
		and
		<code>div[class~=value]</code>
		have the same meaning. The attribute value must immediately follow the
		full stop (
		<code>.</code>
		).

	</p>
	<p>
		UAs may apply selectors using the period (.) notation in XML documents
		if the UA has namespace-specific knowledge that allows it to determine
		which attribute is the "class" attribute for the respective namespace.
		One such example of namespace-specific knowledge is the prose in the
		specification for a particular namespace (e.g. SVG 1.0 <a
			href="#SVG11" rel="biblioentry">[SVG11]<!--{{SVG11}}--></a> describes
		the <a
			href="http://www.w3.org/TR/2001/PR-SVG-20010719/styling.html#ClassAttribute">SVG
			<code>class</code> attribute
		</a> and how a UA should interpret it, and similarly MathML 1.01 <a
			href="#MATHML" rel="biblioentry">[MATHML]<!--{{MATHML}}--></a>
		describes the <a
			href="http://www.w3.org/1999/07/REC-MathML-19990707/chapter2.html#sec2.3.4">MathML
			<code>class</code> attribute
		</a>.)

	</p>
	<div class="example">
		<p>CSS examples:</p>

		<p>
			We can assign style information to all elements with
			<code>class~="pastoral"</code>
			as follows:
		</p>

		<pre>*.pastoral { color: green }  /* all elements with class~=pastoral */</pre>

		<p>or just</p>

		<pre>.pastoral { color: green }  /* all elements with class~=pastoral */</pre>

		<p>
			The following assigns style only to H1 elements with
			<code>class~="pastoral"</code>
			:
		</p>

		<pre>H1.pastoral { color: green }  /* H1 elements with class~=pastoral */</pre>

		<p>
			Given these rules, the first
			<code>H1</code>
			instance below would not have green text, while the second would:
		</p>

		<pre>&lt;H1&gt;Not green&lt;/H1&gt;
			&lt;H1 class="pastoral"&gt;Very green&lt;/H1&gt;</pre>

		<p>
			The following rule matches any
			<code>P</code>
			element whose
			<code>class</code>
			attribute has been assigned a list of <a href="#whitespace">whitespace</a>-separated
			values that includes both
			<code>pastoral</code>
			and
			<code>marine</code>
			:
		</p>

		<pre>p.pastoral.marine { color: green }</pre>

		<p>
			This rule matches when
			<code>class="pastoral blue aqua marine"</code>
			but does not match for
			<code>class="pastoral blue"</code>
			.
		</p>
	</div>

	<p class="note">
		<strong>Note:</strong> Because CSS gives considerable power to the
		"class" attribute, authors could conceivably design their own
		"document language" based on elements with almost no associated
		presentation (such as
		<code>DIV</code>
		and
		<code>SPAN</code>
		in HTML) and assigning style information through the "class"
		attribute. Authors should avoid this practice since the structural
		elements of a document language often have recognized and accepted
		meanings and author-defined classes may not.

	</p>
	<p class="note">
		<strong>Note:</strong> If an element has multiple class attributes,
		their values must be concatenated with spaces between the values
		before searching for the class. As of this time the working group is
		not aware of any manner in which this situation can be reached,
		however, so this behavior is explicitly non-normative in this
		specification.

	</p>
	<h3 id="id-selectors">
		<span class="secno">6.5. </span>ID selectors
	</h3>

	<p>Document languages may contain attributes that are declared to
		be of type ID. What makes attributes of type ID special is that no two
		such attributes can have the same value in a conformant document,
		regardless of the type of the elements that carry them; whatever the
		document language, an ID typed attribute can be used to uniquely
		identify its element. In HTML all ID attributes are named "id"; XML
		applications may name ID attributes differently, but the same
		restriction applies.</p>
	<p>
		An ID-typed attribute of a document language allows authors to assign
		an identifier to one element instance in the document tree. An ID
		selector contains a "number sign" (U+0023,
		<code>#</code>
		) immediately followed by the ID value, which must be an CSS <a
			href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers</a>.
		An ID selector represents an element instance that has an identifier
		that matches the identifier in the ID selector.

	</p>
	<p>Selectors does not specify how a UA knows the ID-typed attribute
		of an element. The UA may, e.g., read a document's DTD, have the
		information hard-coded or ask the user.</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following ID selector represents an
			<code>h1</code>
			element whose ID-typed attribute has the value "chapter1":
		</p>

		<pre>h1#chapter1</pre>

		<p>The following ID selector represents any element whose ID-typed
			attribute has the value "chapter1":</p>

		<pre>#chapter1</pre>

		<p>The following selector represents any element whose ID-typed
			attribute has the value "z98y".</p>

		<pre>*#z98y</pre>
	</div>

	<p class="note">
		<strong>Note:</strong> In XML 1.0 <a href="#XML10" rel="biblioentry">[XML10]<!--{{XML10}}--></a>,
		the information about which attribute contains an element's IDs is
		contained in a DTD or a schema. When parsing XML, UAs do not always
		read the DTD, and thus may not know what the ID of an element is
		(though a UA may have namespace-specific knowledge that allows it to
		determine which attribute is the ID attribute for that namespace). If
		a style sheet author knows or suspects that a UA may not know what the
		ID of an element is, he should use normal attribute selectors instead:
		<code>[name=p371]</code>
		instead of
		<code>#p371</code>
		.

	</p>
	<p>If an element has multiple ID attributes, all of them must be
		treated as IDs for that element for the purposes of the ID selector.
		Such a situation could be reached using mixtures of xml:id, DOM3 Core,
		XML DTDs, and namespace-specific knowledge.</p>
	<h3 id="pseudo-classes">
		<span class="secno">6.6. </span>Pseudo-classes
	</h3>

	<p>The pseudo-class concept is introduced to permit selection based
		on information that lies outside of the document tree or that cannot
		be expressed using the other simple selectors.</p>
	<p>
		A pseudo-class always consists of a "colon" (
		<code>:</code>
		) followed by the name of the pseudo-class and optionally by a value
		between parentheses.

	</p>
	<p>Pseudo-classes are allowed in all sequences of simple selectors
		contained in a selector. Pseudo-classes are allowed anywhere in
		sequences of simple selectors, after the leading type selector or
		universal selector (possibly omitted). Pseudo-class names are
		case-insensitive. Some pseudo-classes are mutually exclusive, while
		others can be applied simultaneously to the same element.
		Pseudo-classes may be dynamic, in the sense that an element may
		acquire or lose a pseudo-class while a user interacts with the
		document.</p>
	<h4 id="dynamic-pseudos">
		<span class="secno">6.6.1. </span>Dynamic pseudo-classes
	</h4>

	<p>Dynamic pseudo-classes classify elements on characteristics
		other than their name, attributes, or content, in principle
		characteristics that cannot be deduced from the document tree.</p>
	<p>Dynamic pseudo-classes do not appear in the document source or
		document tree.</p>
	<h5 id="the-link-pseudo-classes-link-and-visited">
		<span class="secno">6.6.1.1. </span>The <a name="link">link
			pseudo-classes: :link and :visited</a>
	</h5>

	<p>
		User agents commonly display unvisited links differently from
		previously visited ones. Selectors provides the pseudo-classes
		<code>:link</code>
		and
		<code>:visited</code>
		to distinguish them:

	</p>
	<ul>
		<li>The <code>:link</code> pseudo-class applies to links that
			have not yet been visited.

		</li>
		<li>The <code>:visited</code> pseudo-class applies once the link
			has been visited by the user.
		</li>
	</ul>

	<p>
		After some amount of time, user agents may choose to return a visited
		link to the (unvisited) ‘
		<code class="css">:link</code>
		’ state.

	</p>
	<p>The two states are mutually exclusive.</p>
	<div class="example">
		<p>Example:</p>

		<p>
			The following selector represents links carrying class
			<code>external</code>
			and already visited:
		</p>

		<pre>a.external:visited</pre>
	</div>

	<p class="note">
		<strong>Note:</strong> It is possible for style sheet authors to abuse
		the :link and :visited pseudo-classes to determine which sites a user
		has visited without the user's consent.

	</p>
	<p>UAs may therefore treat all links as unvisited links, or
		implement other measures to preserve the user's privacy while
		rendering visited and unvisited links differently.</p>
	<h5 id="the-user-action-pseudo-classes-hover-act">
		<span class="secno">6.6.1.2. </span>The <a name="useraction-pseudos">user
			action pseudo-classes :hover, :active, and :focus</a>
	</h5>

	<p>Interactive user agents sometimes change the rendering in
		response to user actions. Selectors provides three pseudo-classes for
		the selection of an element the user is acting on.</p>
	<ul>
		<li>The <code>:hover</code> pseudo-class applies while the user
			designates an element with a pointing device, but does not
			necessarily activate it. For example, a visual user agent could apply
			this pseudo-class when the cursor (mouse pointer) hovers over a box
			generated by the element. User agents not that do not support <a
			href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">interactive
				media</a> do not have to support this pseudo-class. Some conforming user
			agents that support <a
			href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">interactive
				media</a> may not be able to support this pseudo-class (e.g., a pen
			device that does not detect hovering).

		</li>
		<li>The <code>:active</code> pseudo-class applies while an
			element is being activated by the user. For example, between the
			times the user presses the mouse button and releases it. On systems
			with more than one mouse button, <code>:active</code> applies only to
			the primary or primary activation button (typically the "left" mouse
			button), and any aliases thereof.

		</li>
		<li>The <code>:focus</code> pseudo-class applies while an element
			has the focus (accepts keyboard or mouse events, or other forms of
			input).
		</li>
	</ul>

	<p>
		There may be document language or implementation specific limits on
		which elements can become
		<code>:active</code>
		or acquire
		<code>:focus</code>
		.

	</p>
	<p>These pseudo-classes are not mutually exclusive. An element may
		match several pseudo-classes at the same time.</p>
	<p>
		Selectors doesn't define if the parent of an element that is ‘
		<code class="css">:active</code>
		’ or ‘
		<code class="css">:hover</code>
		’ is also in that state.

	</p>
	<p class="note">
		<strong>Note:</strong> If the ‘
		<code class="css">:hover</code>
		’ state applies to an element because its child is designated by a
		pointing device, then it's possible for ‘
		<code class="css">:hover</code>
		’ to apply to an element that is not underneath the pointing device.

	</p>
	<div class="example">
		<p>Examples:</p>

		<pre>a:link    /* unvisited links */
			a:visited /* visited links */
			a:hover   /* user hovers */
			a:active  /* active links */</pre>

		<p>An example of combining dynamic pseudo-classes:</p>

		<pre>a:focus
			a:focus:hover</pre>

		<p>
			The last selector matches
			<code>a</code>
			elements that are in the pseudo-class :focus and in the pseudo-class
			:hover.
		</p>
	</div>

	<p class="note">
		<strong>Note:</strong> An element can be both ‘
		<code class="css">:visited</code>
		’ and ‘
		<code class="css">:active</code>
		’ (or ‘
		<code class="css">:link</code>
		’ and ‘
		<code class="css">:active</code>
		’).

	</p>
	<h4 id="target-pseudo">
		<span class="secno">6.6.2. </span>The target pseudo-class :target
	</h4>

	<p>Some URIs refer to a location within a resource. This kind of
		URI ends with a "number sign" (#) followed by an anchor identifier
		(called the fragment identifier).</p>
	<p>
		URIs with fragment identifiers link to a certain element within the
		document, known as the target element. For instance, here is a URI
		pointing to an anchor named
		<code>section_2</code>
		in an HTML document:

	</p>
	<pre>http://example.com/html/top.html#section_2</pre>

	<p>
		A target element can be represented by the
		<code>:target</code>
		pseudo-class. If the document's URI has no fragment identifier, then
		the document has no target element.

	</p>
	<div class="example">
		<p>Example:</p>

		<pre>p.note:target</pre>

		<p>
			This selector represents a
			<code>p</code>
			element of class
			<code>note</code>
			that is the target element of the referring URI.
		</p>
	</div>

	<div class="example">
		<p>CSS example:</p>

		<p>
			Here, the
			<code>:target</code>
			pseudo-class is used to make the target element red and place an
			image before it, if there is one:
		</p>

		<pre>*:target { color : red }
			*:target::before { content : url(target.png) }</pre>
	</div>

	<h4 id="lang-pseudo">
		<span class="secno">6.6.3. </span>The language pseudo-class :lang
	</h4>

	<p>
		If the document language specifies how the human language of an
		element is determined, it is possible to write selectors that
		represent an element based on its language. For example, in HTML <a
			href="#HTML401" rel="biblioentry">[HTML401]<!--{{HTML401}}--></a>,
		the language is determined by a combination of the
		<code>lang</code>
		attribute and possibly information from the
		<code>meta</code>
		elements or the protocol (such as HTTP headers). XML uses an attribute
		called
		<code>xml:lang</code>
		, and there may be other document language-specific methods for
		determining the language.

	</p>
	<p>
		The pseudo-class
		<code>:lang(C)</code>
		represents an element that is in language C. Whether an element is
		represented by a
		<code>:lang()</code>
		selector is based solely on the element's language value (normalized
		to BCP 47 syntax if necessary) being equal to the identifier C, or
		beginning with the identifier C immediately followed by "-" (U+002D).
		The matching of C against the element's language value is performed
		case-insensitively. The identifier C does not have to be a valid
		language name.

	</p>
	<p>
		C must be a valid CSS <a
			href="http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifier</a>
		<a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a> and
		must not be empty. (Otherwise, the selector is invalid.)

	</p>
	<p class="note">
		<strong>Note:</strong> It is recommended that documents and protocols
		indicate language using codes from BCP 47 <a href="#BCP47"
			rel="biblioentry">[BCP47]<!--{{BCP47}}--></a> or its successor, and
		by means of "xml:lang" attributes in the case of XML-based documents <a
			href="#XML10" rel="biblioentry">[XML10]<!--{{XML10}}--></a>. See <a
			href="http://www.w3.org/International/questions/qa-lang-2or3.html">
			"FAQ: Two-letter or three-letter language codes."</a>

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The two following selectors represent an HTML document that is in
			Belgian French or German. The two next selectors represent
			<code>q</code>
			quotations in an arbitrary element in Belgian French or German.
		</p>

		<pre>html:lang(fr-be)
			html:lang(de)
			:lang(fr-be) &gt; q
			:lang(de) &gt; q</pre>
	</div>

	<p>
		The difference between
		<code>:lang(C)</code>
		and the ‘
		<code class="css">|=</code>
		’ operator is that the ‘
		<code class="css">|=</code>
		’ operator only performs a comparison against a given attribute on the
		element, while the
		<code>:lang(C)</code>
		pseudo-class uses the UAs knowledge of the document's semantics to
		perform the comparison.

	</p>
	<div class="example">
		<p>
			In this HTML example, only the BODY matches
			<code>[lang|=fr]</code>
			(because it has a LANG attribute) but both the BODY and the P match
			<code>:lang(fr)</code>
			(because both are in French). The P does not match the
			<code>[lang|=fr]</code>
			because it does not have a LANG attribute.
		</p>

		<pre>&lt;body lang=fr&gt;
			&lt;p&gt;Je suis français.&lt;/p&gt;
			&lt;/body&gt;</pre>
	</div>

	<h4 id="UIstates">
		<span class="secno">6.6.4. </span>The UI element states pseudo-classes
	</h4>

	<h5 id="enableddisabled">
		<span class="secno">6.6.4.1. </span>The :enabled and :disabled
		pseudo-classes
	</h5>

	<p>
		The
		<code>:enabled</code>
		pseudo-class represents user interface elements that are in an enabled
		state; such elements have a corresponding disabled state.

	</p>
	<p>
		Conversely, the
		<code>:disabled</code>
		pseudo-class represents user interface elements that are in a disabled
		state; such elements have a corresponding enabled state.

	</p>
	<p>
		What constitutes an enabled state, a disabled state, and a user
		interface element is language-dependent. In a typical document most
		elements will be neither
		<code>:enabled</code>
		nor
		<code>:disabled</code>
		.

	</p>
	<p class="note">
		<strong>Note:</strong> CSS properties that might affect a user’s
		ability to interact with a given user interface element do not affect
		whether it matches
		<code>:enabled</code>
		or
		<code>:disabled</code>
		; e.g., the
		<code>display</code>
		and
		<code>visibility</code>
		properties have no effect on the enabled/disabled state of an element.

	</p>
	<h5 id="checked">
		<span class="secno">6.6.4.2. </span>The :checked pseudo-class
	</h5>

	<p>
		Radio and checkbox elements can be toggled by the user. Some menu
		items are "checked" when the user selects them. When such elements are
		toggled "on" the
		<code>:checked</code>
		pseudo-class applies. While the
		<code>:checked</code>
		pseudo-class is dynamic in nature, and can altered by user action,
		since it can also be based on the presence of semantic attributes in
		the document, it applies to all media. For example, the
		<code>:checked</code>
		pseudo-class initially applies to such elements that have the HTML4
		<code>selected</code>
		and
		<code>checked</code>
		attributes as described in <a
			href="http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.2.1">Section
			17.2.1 of HTML4</a>, but of course the user can toggle "off" such
		elements in which case the
		<code>:checked</code>
		pseudo-class would no longer apply.

	</p>
	<h5 id="indeterminate">
		<span class="secno">6.6.4.3. </span>The :indeterminate pseudo-class
	</h5>

	<div class="note">
		<p>
			<strong>Note:</strong> Radio and checkbox elements can be toggled by
			the user, but are sometimes in an indeterminate state, neither
			checked nor unchecked. This can be due to an element attribute, or
			DOM manipulation.
		</p>

		<p>
			A future version of this specification may introduce an
			<code>:indeterminate</code>
			pseudo-class that applies to such elements.
			<!--While the <code>:indeterminate</code> pseudo-class is dynamic in
					nature, and is altered by user action, since it can also be based on
					the presence of an element attribute, it applies to all media.</p>

					<p>Components of a radio-group initialized with no pre-selected choice
						are an example of :indeterminate state.-->
		</p>
	</div>

	<h4 id="structural-pseudos">
		<span class="secno">6.6.5. </span>Structural pseudo-classes
	</h4>

	<p>
		Selectors introduces the concept of
		<dfn id="structural-pseudo-classes">structural pseudo-classes</dfn>
		to permit selection based on extra information that lies in the
		document tree but cannot be represented by other simple selectors or
		combinators.

	</p>
	<p>Standalone text and other non-element nodes are not counted when
		calculating the position of an element in the list of children of its
		parent. When calculating the position of an element in the list of
		children of its parent, the index numbering starts at 1.</p>
	<h5 id="root-pseudo">
		<span class="secno">6.6.5.1. </span>:root pseudo-class
	</h5>

	<p>
		The
		<code>:root</code>
		pseudo-class represents an element that is the root of the document.
		In HTML 4, this is always the
		<code>HTML</code>
		element.

	</p>
	<h5 id="nth-child-pseudo">
		<span class="secno">6.6.5.2. </span>:nth-child() pseudo-class
	</h5>

	<p>
		The
		<code>
			:nth-child(
			<var>a</var>
			<code>n</code>
			+
			<var>b</var>
			)
		</code>
		pseudo-class notation represents an element that has
		<var>a</var>
		<code>n</code>
		+
		<var>b</var>
		-1 siblings <strong>before</strong> it in the document tree, for any
		positive integer or zero value of
		<code>n</code>
		, and has a parent element. For values of
		<var>a</var>
		and
		<var>b</var>
		greater than zero, this effectively divides the element's children
		into groups of
		<var>a</var>
		elements (the last group taking the remainder), and selecting the
		<var>b</var>
		th element of each group. For example, this allows the selectors to
		address every other row in a table, and could be used to alternate the
		color of paragraph text in a cycle of four. The
		<var>a</var>
		and
		<var>b</var>
		values must be integers (positive, negative, or zero). The index of
		the first child of an element is 1.

	</p>
	<p>
		In addition to this,
		<code>:nth-child()</code>
		can take ‘
		<code class="css">
			<code>odd</code>
		</code>
		’ and ‘
		<code class="css">
			<code>even</code>
		</code>
		’ as arguments instead. ‘
		<code class="css">
			<code>odd</code>
		</code>
		’ has the same signification as
		<code>2n+1</code>
		, and ‘
		<code class="css">
			<code>even</code>
		</code>
		’ has the same signification as
		<code>2n</code>
		.

	</p>
	<p>
		The argument to
		<code>:nth-child()</code>
		must match the grammar below, where
		<code>INTEGER</code>
		matches the token
		<code>[0-9]+</code>
		and the rest of the tokenization is given by the <a href="#lex">Lexical
			scanner</a> in section 10.2:

	</p>
	<pre>nth
		: S* [ ['-'|'+']? INTEGER? {N} [ S* ['-'|'+'] S* INTEGER ]? |
		['-'|'+']? INTEGER | {O}{D}{D} | {E}{V}{E}{N} ] S*
		;</pre>

	<div class="example">
		<p>Examples:</p>

		<pre>tr:nth-child(2n+1) /* represents every odd row of an HTML table */
			tr:nth-child(odd)  /* same */
			tr:nth-child(2n+0) /* represents every even row of an HTML table */
			tr:nth-child(even) /* same */

			/* Alternate paragraph colours in CSS */
			p:nth-child(4n+1) { color: navy; }
			p:nth-child(4n+2) { color: green; }
			p:nth-child(4n+3) { color: maroon; }
			p:nth-child(4n+4) { color: purple; }</pre>
	</div>

	<p>
		When the value
		<var>b</var>
		is preceded by a negative sign, the "+" character in the expression
		must be removed (it is effectively replaced by the "-" character
		indicating the negative value of
		<var>b</var>
		).

	</p>
	<div class="example">
		<p>Examples:</p>

		<pre>:nth-child(10n-1)  /* represents the 9th, 19th, 29th, etc, element */
			:nth-child(10n+9)  /* Same */
			:nth-child(10n+-1) /* Syntactically invalid, and would be ignored */</pre>
	</div>

	<p>
		When
		<var>a</var>
		=0, the
		<var>a</var>
		<code>n</code>
		part need not be included (unless the
		<var>b</var>
		part is already omitted). When
		<var>a</var>
		<code>n</code>
		is not included and
		<var>b</var>
		is non-negative, the
		<code>+</code>
		sign before
		<var>b</var>
		(when allowed) may also be omitted. In this case the syntax simplifies
		to
		<code>
			:nth-child(
			<var>b</var>
			)
		</code>
		.

	</p>
	<div class="example">
		<p>Examples:</p>

		<pre>foo:nth-child(0n+5)   /* represents an element foo that is the 5th child
			of its parent element */
			foo:nth-child(5)      /* same */</pre>
	</div>

	<p>
		When
		<var>a</var>
		=1, or
		<var>a</var>
		=-1, the number may be omitted from the rule.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>The following selectors are therefore equivalent:</p>

		<pre>bar:nth-child(1n+0)   /* represents all bar elements, specificity (0,1,1) */
			bar:nth-child(n+0)    /* same */
			bar:nth-child(n)      /* same */
			bar                   /* same but lower specificity (0,0,1) */</pre>
	</div>

	<p>
		If
		<var>b</var>
		=0, then every
		<var>a</var>
		th element is picked. In such a case, the +
		<var>b</var>
		(or -
		<var>b</var>
		) part may be omitted unless the
		<var>a</var>
		part is already omitted.

	</p>
	<div class="example">
		<p>Examples:</p>

		<pre>tr:nth-child(2n+0) /* represents every even row of an HTML table */
			tr:nth-child(2n) /* same */</pre>
	</div>

	<p>
		Whitespace is permitted after the "(", before the ")", and on either
		side of the "+" or "-" that separates the
		<var>a</var>
		<code>n</code>
		and
		<var>b</var>
		parts when both are present.

	</p>
	<div class="example">
		<p>Valid Examples with white space:</p>

		<pre>:nth-child( 3n + 1 )
			:nth-child( +3n - 2 )
			:nth-child( -n+ 6)
			:nth-child( +6 )
		</pre>

		<p>Invalid Examples with white space:</p>

		<pre>:nth-child(3 n)
			:nth-child(+ 2n)
			:nth-child(+ 2)
		</pre>
	</div>

	<p>
		If both
		<var>a</var>
		and
		<var>b</var>
		are equal to zero, the pseudo-class represents no element in the
		document tree.

	</p>
	<p>
		The value
		<var>a</var>
		can be negative, but only the positive values of
		<var>a</var>
		<code>n</code>
		+
		<var>b</var>
		, for
		<code>n</code>
		≥0, may represent an element in the document tree.

	</p>
	<div class="example">
		<p>Example:</p>

		<pre>html|tr:nth-child(-n+6)  /* represents the 6 first rows of XHTML tables */</pre>
	</div>

	<h5 id="nth-last-child-pseudo">
		<span class="secno">6.6.5.3. </span>:nth-last-child() pseudo-class
	</h5>

	<p>
		The
		<code>
			:nth-last-child(
			<var>a</var>
			n+
			<var>b</var>
			)
		</code>
		pseudo-class notation represents an element that has
		<var>a</var>
		<code>n</code>
		+
		<var>b</var>
		-1 siblings <strong>after</strong> it in the document tree, for any
		positive integer or zero value of
		<code>n</code>
		, and has a parent element. See <a href="#nth-child-pseudo"><code>:nth-child()</code></a>
		pseudo-class for the syntax of its argument. It also accepts the ‘
		<code class="css">
			<code>even</code>
		</code>
		’ and ‘
		<code class="css">
			<code>odd</code>
		</code>
		’ values as arguments.

	</p>
	<div class="example">
		<p>Examples:</p>

		<pre>tr:nth-last-child(-n+2)    /* represents the two last rows of an HTML table */

			foo:nth-last-child(odd)    /* represents all odd foo elements in their parent element,
			counting from the last one */</pre>
	</div>

	<h5 id="nth-of-type-pseudo">
		<span class="secno">6.6.5.4. </span>:nth-of-type() pseudo-class
	</h5>

	<p>
		The
		<code>
			:nth-of-type(
			<var>a</var>
			n+
			<var>b</var>
			)
		</code>
		pseudo-class notation represents an element that has
		<var>a</var>
		<code>n</code>
		+
		<var>b</var>
		-1 siblings with the same expanded element name <strong>before</strong>
		it in the document tree, for any zero or positive integer value of
		<code>n</code>
		, and has a parent element. See <a href="#nth-child-pseudo"><code>:nth-child()</code></a>
		pseudo-class for the syntax of its argument. It also accepts the ‘
		<code class="css">
			<code>even</code>
		</code>
		’ and ‘
		<code class="css">
			<code>odd</code>
		</code>
		’ values.

	</p>
	<div class="example">
		<p>CSS example:</p>

		<p>This allows an author to alternate the position of floated
			images:</p>

		<pre>img:nth-of-type(2n+1) { float: right; }
			img:nth-of-type(2n) { float: left; }</pre>
	</div>

	<h5 id="nth-last-of-type-pseudo">
		<span class="secno">6.6.5.5. </span>:nth-last-of-type() pseudo-class
	</h5>

	<p>
		The
		<code>
			:nth-last-of-type(
			<var>a</var>
			n+
			<var>b</var>
			)
		</code>
		pseudo-class notation represents an element that has
		<var>a</var>
		<code>n</code>
		+
		<var>b</var>
		-1 siblings with the same expanded element name <strong>after</strong>
		it in the document tree, for any zero or positive integer value of
		<code>n</code>
		, and has a parent element. See <a href="#nth-child-pseudo"><code>:nth-child()</code></a>
		pseudo-class for the syntax of its argument. It also accepts the ‘
		<code class="css">
			<code>even</code>
		</code>
		’ and ‘
		<code class="css">
			<code>odd</code>
		</code>
		’ values.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			To represent all
			<code>h2</code>
			children of an XHTML
			<code>body</code>
			except the first and last, one could use the following selector:
		</p>

		<pre>body &gt; h2:nth-of-type(n+2):nth-last-of-type(n+2)</pre>

		<p>
			In this case, one could also use
			<code>:not()</code>
			, although the selector ends up being just as long:
		</p>

		<pre>body &gt; h2:not(:first-of-type):not(:last-of-type)</pre>
	</div>

	<h5 id="first-child-pseudo">
		<span class="secno">6.6.5.6. </span>:first-child pseudo-class
	</h5>

	<p>
		Same as
		<code>:nth-child(1)</code>
		. The
		<code>:first-child</code>
		pseudo-class represents an element that is the first child of some
		other element.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following selector represents a
			<code>p</code>
			element that is the first child of a
			<code>div</code>
			element:
		</p>

		<pre>div &gt; p:first-child</pre>

		<p>
			This selector can represent the
			<code>p</code>
			inside the
			<code>div</code>
			of the following fragment:
		</p>

		<pre>&lt;p&gt; The last P before the note.&lt;/p&gt;
			&lt;div class="note"&gt;
			&lt;p&gt; The first P inside the note.&lt;/p&gt;
			&lt;/div&gt;</pre>
		but cannot represent the second
		<code>p</code>
		in the following fragment:
		<pre>&lt;p&gt; The last P before the note.&lt;/p&gt;
			&lt;div class="note"&gt;
			&lt;h2&gt; Note &lt;/h2&gt;
			&lt;p&gt; The first P inside the note.&lt;/p&gt;
			&lt;/div&gt;</pre>

		<p>The following two selectors are usually equivalent:</p>

		<pre>* &gt; a:first-child /* a is first child of any element */
			a:first-child /* Same (assuming a is not the root element) */</pre>
	</div>

	<h5 id="last-child-pseudo">
		<span class="secno">6.6.5.7. </span>:last-child pseudo-class
	</h5>

	<p>
		Same as
		<code>:nth-last-child(1)</code>
		. The
		<code>:last-child</code>
		pseudo-class represents an element that is the last child of some
		other element.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			The following selector represents a list item
			<code>li</code>
			that is the last child of an ordered list
			<code>ol</code>
			.

		</p>
		<pre>ol &gt; li:last-child</pre>
	</div>

	<h5 id="first-of-type-pseudo">
		<span class="secno">6.6.5.8. </span>:first-of-type pseudo-class
	</h5>

	<p>
		Same as
		<code>:nth-of-type(1)</code>
		. The
		<code>:first-of-type</code>
		pseudo-class represents an element that is the first sibling of its
		type in the list of children of its parent element.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			The following selector represents a definition title
			<code>dt</code>
			inside a definition list
			<code>dl</code>
			, this
			<code>dt</code>
			being the first of its type in the list of children of its parent
			element.
		</p>

		<pre>dl dt:first-of-type</pre>

		<p>
			It is a valid description for the first two
			<code>dt</code>
			elements in the following example but not for the third one:
		</p>

		<pre>&lt;dl&gt;
			&lt;dt&gt;gigogne&lt;/dt&gt;
			&lt;dd&gt;
			&lt;dl&gt;
			&lt;dt&gt;fusée&lt;/dt&gt;
			&lt;dd&gt;multistage rocket&lt;/dd&gt;
			&lt;dt&gt;table&lt;/dt&gt;
			&lt;dd&gt;nest of tables&lt;/dd&gt;
			&lt;/dl&gt;
			&lt;/dd&gt;
			&lt;/dl&gt;</pre>
	</div>

	<h5 id="last-of-type-pseudo">
		<span class="secno">6.6.5.9. </span>:last-of-type pseudo-class
	</h5>

	<p>
		Same as
		<code>:nth-last-of-type(1)</code>
		. The
		<code>:last-of-type</code>
		pseudo-class represents an element that is the last sibling of its
		type in the list of children of its parent element.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			The following selector represents the last data cell
			<code>td</code>
			of a table row
			<code>tr</code>
			.
		</p>

		<pre>tr &gt; td:last-of-type</pre>
	</div>

	<h5 id="only-child-pseudo">
		<span class="secno">6.6.5.10. </span>:only-child pseudo-class
	</h5>

	<p>
		Represents an element that has a parent element and whose parent
		element has no other element children. Same as
		<code>:first-child:last-child</code>
		or
		<code>:nth-child(1):nth-last-child(1)</code>
		, but with a lower specificity.

	</p>
	<h5 id="only-of-type-pseudo">
		<span class="secno">6.6.5.11. </span>:only-of-type pseudo-class
	</h5>

	<p>
		Represents an element that has a parent element and whose parent
		element has no other element children with the same expanded element
		name. Same as
		<code>:first-of-type:last-of-type</code>
		or
		<code>:nth-of-type(1):nth-last-of-type(1)</code>
		, but with a lower specificity.

	</p>
	<h5 id="empty-pseudo">
		<span class="secno">6.6.5.12. </span>:empty pseudo-class
	</h5>

	<p>
		The
		<code>:empty</code>
		pseudo-class represents an element that has no children at all. In
		terms of the document tree, only element nodes and content nodes (such
		as DOM <a href="#DOM-LEVEL-3-CORE" rel="biblioentry">[DOM-LEVEL-3-CORE]<!--{{DOM-LEVEL-3-CORE}}--></a>
		text nodes, CDATA nodes, and entity references) whose data has a
		non-zero length must be considered as affecting emptiness; comments,
		processing instructions, and other nodes must not affect whether an
		element is considered empty or not.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			<code>p:empty</code>
			is a valid representation of the following fragment:
		</p>

		<pre>&lt;p&gt;&lt;/p&gt;</pre>

		<p>
			<code>foo:empty</code>
			is not a valid representation for the following fragments:
		</p>

		<pre>&lt;foo&gt;bar&lt;/foo&gt;</pre>

		<pre>&lt;foo&gt;&lt;bar&gt;bla&lt;/bar&gt;&lt;/foo&gt;</pre>

		<pre>&lt;foo&gt;this is not &lt;bar&gt;:empty&lt;/bar&gt;&lt;/foo&gt;</pre>
	</div>

	<h4 id="content-selectors">
		<span class="secno">6.6.6. </span>Blank
	</h4>
	<!-- It's the Return of Appendix H!!! Run away! -->

	<p>
		This section intentionally left blank. (This section previously
		defined a
		<code>:contains()</code>
		pseudo-class.)
	</p>
	<!-- (used to be :contains()) -->

	<h4 id="negation">
		<span class="secno">6.6.7. </span>The negation pseudo-class
	</h4>

	<p>
		The negation pseudo-class,
		<code>
			:not(
			<var>X</var>
			)
		</code>
		, is a functional notation taking a <a href="#simple-selectors-dfn">simple
			selector</a> (excluding the negation pseudo-class itself) as an argument.
		It represents an element that is not represented by its argument.

	</p>
	<p>
		Negations may not be nested;
		<code>:not(:not(...))</code>
		is invalid. Note also that since pseudo-elements are not simple
		selectors, they are not a valid argument to
		<code>:not()</code>
		.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following selector matches all
			<code>button</code>
			elements in an HTML document that are not disabled.
		</p>

		<pre>button:not([DISABLED])</pre>

		<p>
			The following selector represents all but
			<code>FOO</code>
			elements.
		</p>

		<pre>*:not(FOO)</pre>

		<p>The following group of selectors represents all HTML elements
			except links.</p>

		<pre>html|*:not(:link):not(:visited)</pre>
	</div>

	<p>Default namespace declarations do not affect the argument of the
		negation pseudo-class unless the argument is a universal selector or a
		type selector.</p>
	<div class="example">
		<p>Examples:</p>

		<p>Assuming that the default namespace is bound to
			"http://example.com/", the following selector represents all elements
			that are not in that namespace:</p>

		<pre>*|*:not(*)</pre>

		<p>
			The following selector matches any element that is not being hovered,
			regardless of its namespace. In particular, it is not limited to only
			matching elements in the default namespace that are not being
			hovered, and elements not in the default namespace don't match the
			rule when they <em>are</em> being hovered.
		</p>

		<pre>*|*:not(:hover)</pre>
	</div>

	<p class="note">
		<strong>Note</strong>: the :not() pseudo allows useless selectors to
		be written. For instance
		<code>:not(*|*)</code>
		, which represents no element at all, or
		<code>foo:not(bar)</code>
		, which is equivalent to
		<code>foo</code>
		but with a higher specificity.

	</p>
	<h2 id="pseudo-elements">
		<span class="secno">7. </span>Pseudo-elements
	</h2>

	<p>
		Pseudo-elements create abstractions about the document tree beyond
		those specified by the document language. For instance, document
		languages do not offer mechanisms to access the first letter or first
		line of an element's content. Pseudo-elements allow authors to refer
		to this otherwise inaccessible information. Pseudo-elements may also
		provide authors a way to refer to content that does not exist in the
		source document (e.g., the
		<code>::before</code>
		and
		<code>::after</code>
		pseudo-elements give access to generated content).

	</p>
	<p>
		A pseudo-element is made of two colons (
		<code>::</code>
		) followed by the name of the pseudo-element.

	</p>
	<p>
		This
		<code>::</code>
		notation is introduced by the current document in order to establish a
		discrimination between pseudo-classes and pseudo-elements. For
		compatibility with existing style sheets, user agents must also accept
		the previous one-colon notation for pseudo-elements introduced in CSS
		levels 1 and 2 (namely,
		<code>:first-line</code>
		,
		<code>:first-letter</code>
		,
		<code>:before</code>
		and
		<code>:after</code>
		). This compatibility is not allowed for the new pseudo-elements
		introduced in this specification.

	</p>
	<p>
		Only one pseudo-element may appear per selector, and if present it
		must appear after the sequence of simple selectors that represents the
		<a href="#subject">subjects</a> of the selector. <span class="note"><strong>Note:</strong>
			A future version of this specification may allow multiple
			pseudo-elements per selector.</span>

	</p>
	<h3 id="first-line">
		<span class="secno">7.1. </span>The ::first-line pseudo-element
	</h3>

	<p>
		The
		<code>::first-line</code>
		pseudo-element describes the contents of the first formatted line of
		an element.

	</p>
	<div class="example">
		<p>CSS example:</p>

		<pre>p::first-line { text-transform: uppercase }</pre>

		<p>
			The above rule means "change the letters of the first line of every
			<code>p</code>
			element to uppercase".
		</p>

		<p>
			The selector
			<code>p::first-line</code>
			does not match any real document element. It does match a
			pseudo-element that conforming user agents will insert at the
			beginning of every
			<code>p</code>
			element.
		</p>
	</div>

	<p>Note that the length of the first line depends on a number of
		factors, including the width of the page, the font size, etc. Thus, an
		ordinary HTML paragraph such as:</p>
	<pre>&lt;P&gt;This is a somewhat long HTML 
		paragraph that will be broken into several 
		lines. The first line will be identified
		by a fictional tag sequence. The other lines 
		will be treated as ordinary lines in the 
		paragraph.&lt;/P&gt;
	</pre>

	<p>the lines of which happen to be broken as follows:</p>
	<pre>THIS IS A SOMEWHAT LONG HTML PARAGRAPH THAT
		will be broken into several lines. The first
		line will be identified by a fictional tag 
		sequence. The other lines will be treated as 
		ordinary lines in the paragraph.
	</pre>

	<p>
		This paragraph might be "rewritten" by user agents to include the <em>fictional
			tag sequence</em> for
		<code>::first-line</code>
		. This fictional tag sequence helps to show how properties are
		inherited.

	</p>
	<pre>&lt;P&gt;<b>&lt;P::first-line&gt;</b> This is a somewhat long HTML 
		paragraph that <b>&lt;/P::first-line&gt;</b> will be broken into several
		lines. The first line will be identified 
		by a fictional tag sequence. The other lines 
		will be treated as ordinary lines in the 
		paragraph.&lt;/P&gt;
	</pre>

	<p>
		If a pseudo-element breaks up a real element, the desired effect can
		often be described by a fictional tag sequence that closes and then
		re-opens the element. Thus, if we mark up the previous paragraph with
		a
		<code>span</code>
		element:

	</p>
	<pre>&lt;P&gt;<b>&lt;SPAN class="test"&gt;</b> This is a somewhat long HTML
		paragraph that will be broken into several
		lines.<b>&lt;/SPAN&gt;</b> The first line will be identified
		by a fictional tag sequence. The other lines 
		will be treated as ordinary lines in the 
		paragraph.&lt;/P&gt;
	</pre>

	<p>
		the user agent could simulate start and end tags for
		<code>span</code>
		when inserting the fictional tag sequence for
		<code>::first-line</code>
		.

	</p>
	<pre>&lt;P&gt;&lt;P::first-line&gt;<b>&lt;SPAN class="test"&gt;</b> This is a
		somewhat long HTML
		paragraph that will <b>&lt;/SPAN&gt;</b>&lt;/P::first-line&gt;<b>&lt;SPAN class="test"&gt;</b> be
		broken into several
		lines.<b>&lt;/SPAN&gt;</b> The first line will be identified
		by a fictional tag sequence. The other lines
		will be treated as ordinary lines in the 
		paragraph.&lt;/P&gt;
	</pre>

	<h4 id="first-formatted-line">
		<span class="secno">7.1.1. </span>
		<dfn id="first-formatted-line0">First formatted line</dfn>
		definition in CSS
	</h4>

	<p>
		In CSS, the
		<code>::first-line</code>
		pseudo-element can only have an effect when attached to a block-like
		container such as a block box, inline-block, table-caption, or
		table-cell.

	</p>
	<p>
		The first formatted line of an element may occur inside a block-level
		descendant in the same flow (i.e., a block-level descendant that is
		not out-of-flow due to floating or positioning). For example, the
		first line of the
		<code>DIV</code>
		in
		<code>&lt;DIV&gt;&lt;P&gt;This line...&lt;/P&gt;&lt;/DIV&gt;</code>
		is the first line of the
		<code>P</code>
		(assuming that both
		<code>P</code>
		and
		<code>DIV</code>
		are block-level).

	</p>
	<p>
		The first line of a table-cell or inline-block cannot be the first
		formatted line of an ancestor element. Thus, in
		<code>&lt;DIV&gt;&lt;P STYLE="display:
			inline-block"&gt;Hello&lt;BR&gt;Goodbye&lt;/P&gt;
			etcetera&lt;/DIV&gt;</code>
		the first formatted line of the
		<code>DIV </code>
		is not the line "Hello".

	</p>
	<p class="note">
		<strong>Note:</strong> Note that the first line of the
		<code>p</code>
		in this fragment:
		<code>&lt;p&gt;&lt;br&gt;First...</code>
		doesn't contain any letters (assuming the default style for
		<code>br</code>
		in HTML 4). The word "First" is not on the first formatted line.

	</p>
	<p>
		A UA should act as if the fictional start tags of the
		<code>::first-line</code>
		pseudo-elements were nested just inside the innermost enclosing
		block-level element. (Since CSS1 and CSS2 were silent on this case,
		authors should not rely on this behavior.) For example, the fictional
		tag sequence for

	</p>
	<pre>&lt;DIV&gt;
		&lt;P&gt;First paragraph&lt;/P&gt;
		&lt;P&gt;Second paragraph&lt;/P&gt;
		&lt;/DIV&gt;
	</pre>

	<p>is</p>
	<pre>&lt;DIV&gt;
		&lt;P&gt;&lt;DIV::first-line&gt;&lt;P::first-line&gt;First paragraph&lt;/P::first-line&gt;&lt;/DIV::first-line&gt;&lt;/P&gt;
		&lt;P&gt;&lt;P::first-line&gt;Second paragraph&lt;/P::first-line&gt;&lt;/P&gt;
		&lt;/DIV&gt;
	</pre>

	<p>
		The
		<code>::first-line</code>
		pseudo-element is similar to an inline-level element, but with certain
		restrictions. The following CSS properties apply to a
		<code>::first-line</code>
		pseudo-element: font properties, color property, background
		properties, ‘
		<code class="property">word-spacing</code>
		’, ‘
		<code class="property">letter-spacing</code>
		’, ‘
		<code class="property">text-decoration</code>
		’, ‘
		<code class="property">vertical-align</code>
		’, ‘
		<code class="property">text-transform</code>
		’, ‘
		<code class="property">line-height</code>
		’. UAs may apply other properties as well.

	</p>
	<p>
		During CSS inheritance, the portion of a child element that occurs on
		the first line only inherits properties applicable to the
		<code>::first-line</code>
		pseudo-element from the
		<code>::first-line</code>
		pseudo-element. For all other properties inheritence is from the
		non-pseudo-element parent of the first line pseudo element. (The
		portion of a child element that does not occur on the first line
		always inherits from the parent of that child.)

	</p>
	<h3 id="first-letter">
		<span class="secno">7.2. </span>The ::first-letter pseudo-element
	</h3>

	<p>
		The
		<code>::first-letter</code>
		pseudo-element represents the first letter of an element, if it is not
		preceded by any other content (such as images or inline tables) on its
		line. The ::first-letter pseudo-element may be used for "initial caps"
		and "drop caps", which are common typographical effects.

	</p>
	<p>
		Punctuation (i.e, characters defined in Unicode in the "open" (Ps),
		"close" (Pe), "initial" (Pi). "final" (Pf) and "other" (Po)
		punctuation classes), that precedes or follows the first letter should
		be included. <a href="#UNICODE" rel="biblioentry">[UNICODE]<!--{{!UNICODE}}--></a>

	</p>

	<p>
		The
		<code>::first-letter</code>
		also applies if the first letter is in fact a digit, e.g., the "6" in
		"67 million dollars is a lot of money."

	</p>
	<p class="note">
		<strong>Note:</strong> In some cases the
		<code>::first-letter</code>
		pseudo-element should include more than just the first non-punctuation
		character on a line. For example, combining characters must be kept
		with their base character. Additionally, some languages may have
		specific rules about how to treat certain letter combinations. The UA
		definition of
		<code>::first-letter</code>
		should include at least the default grapheme cluster as defined by
		UAX29 and may include more than that as appropriate. In Dutch, for
		example, if the letter combination "ij" appears at the beginning of an
		element, both letters should be considered within the
		<code>::first-letter</code>
		pseudo-element. <a href="#UAX29" rel="biblioentry">[UAX29]<!--{{UAX29}}--></a>

	</p>
	<p>
		If the letters that would form the
		<code>::first-letter</code>
		are not in the same element, such as "‘
		<code class="css">
			T" in
			<code>&lt;p&gt;'&lt;em&gt;T...</code>
			, the UA may create a
			<code>::first-letter</code>
			pseudo-element from one of the elements, both elements, or simply not
			create a pseudo-element.
		</code>

	</p>
	<p>Similarly, if the first letter(s) of the block are not at the
		start of the line (for example due to bidirectional reordering), then
		the UA need not create the pseudo-element(s).</p>
	<div class="example">
		<p>Example:</p>

		<p>
			<a name="overlapping-example">The following CSS and HTML example</a>
			illustrates how overlapping pseudo-elements may interact. The first
			letter of each P element will be green with a font size of ’24pt'.
			The rest of the first formatted line will be ‘
			<code class="property">blue</code>
			’ while the rest of the paragraph will be ‘
			<code class="property">red</code>
			’.
		</p>

		<pre>p { color: red; font-size: 12pt }
			p::first-letter { color: green; font-size: 200% }
			p::first-line { color: blue }

			&lt;P&gt;Some text that ends up on two lines&lt;/P&gt;</pre>

		<p>
			Assuming that a line break will occur before the word "ends", the <span
				class="index-inst" id="fictional-tag-sequence"
				title="fictional tag
																																																																		 sequence">fictional
				tag sequence</span> for this fragment might be:
		</p>

		<pre>&lt;P&gt;
			&lt;P::first-line&gt;
			&lt;P::first-letter&gt; 
			S 
			&lt;/P::first-letter&gt;ome text that 
			&lt;/P::first-line&gt; 
			ends up on two lines 
			&lt;/P&gt;</pre>

		<p>
			Note that the
			<code>::first-letter</code>
			element is inside the
			<code>::first-line</code>
			element. Properties set on
			<code>::first-line</code>
			are inherited by
			<code>::first-letter</code>
			, but are overridden if the same property is set on
			<code>::first-letter</code>
			.
		</p>
	</div>

	<p>
		The first letter must occur on the <a href="#first-formatted-line">first
			formatted line.</a> For example, in this HTML fragment:
		<code>&lt;p&gt;&lt;br&gt;First...</code>
		the first line doesn't contain any letters and
		<code>::first-letter</code>
		doesn't match anything (assuming the default style for
		<code>br</code>
		in HTML 4). In particular, it does not match the "F" of "First."

	</p>
	<h4 id="application-in-css">
		<span class="secno">7.2.1. </span>Application in CSS
	</h4>

	<p>
		In CSS, the
		<code>::first-letter</code>
		pseudo-element applies to block-like containers such as block,
		list-item, table-cell, table-caption, and inline-block elements. <span
			class="note"><strong>Note:</strong> A future version of this
			specification may allow this pseudo-element to apply to more display
			types.</span>

	</p>
	<p>
		The
		<code>::first-letter</code>
		pseudo-element can be used with all such elements that contain text,
		or that have a descendant in the same flow that contains text. A UA
		should act as if the fictional start tag of the ::first-letter
		pseudo-element is just before the first text of the element, even if
		that first text is in a descendant.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>The fictional tag sequence for this HTML fragment:</p>
		<pre>&lt;div&gt;
			&lt;p&gt;The first text.</pre>

		<p>is:</p>
		<pre>&lt;div&gt;
			&lt;p&gt;&lt;div::first-letter&gt;&lt;p::first-letter&gt;T&lt;/...&gt;&lt;/...&gt;he first text.</pre>
	</div>

	<p>
		In CSS the first letter of a table-cell or inline-block cannot be the
		first letter of an ancestor element. Thus, in
		<code>&lt;DIV&gt;&lt;P STYLE="display:
			inline-block"&gt;Hello&lt;BR&gt;Goodbye&lt;/P&gt;
			etcetera&lt;/DIV&gt;</code>
		the first letter of the
		<code>DIV</code>
		is not the letter "H". In fact, the
		<code>DIV</code>
		doesn't have a first letter.

	</p>
	<p>
		If an element is a list item (‘
		<code class="css">display: list-item</code>
		’), the
		<code>::first-letter</code>
		applies to the first letter in the principal box after the marker. UAs
		may ignore
		<code>::first-letter</code>
		on list items with ‘
		<code class="css">list-style-position: inside</code>
		’. If an element has
		<code>::before</code>
		or
		<code>::after</code>
		content, the
		<code>::first-letter</code>
		applies to the first letter of the element <em>including</em> that
		content.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			After the rule
			<code>p::before {content: "Note: "}</code>
			, the selector
			<code>p::first-letter</code>
			matches the "N" of "Note".
		</p>
	</div>

	<p>
		In CSS a ::first-line pseudo-element is similar to an inline-level
		element if its ‘
		<code class="property">float</code>
		’ property is ‘
		<code class="property">none</code>
		’; otherwise, it is similar to a floated element. The following
		properties that apply to
		<code>::first-letter</code>
		pseudo-elements: font properties, ‘
		<code class="property">text-decoration</code>
		’, ‘
		<code class="property">text-transform</code>
		’, ‘
		<code class="property">letter-spacing</code>
		’, ‘
		<code class="property">word-spacing</code>
		’ (when appropriate), ‘
		<code class="property">line-height</code>
		’, ‘
		<code class="property">float</code>
		’, ‘
		<code class="property">vertical-align</code>
		’ (only if ‘
		<code class="property">float</code>
		’ is ‘
		<code class="property">none</code>
		’), margin properties, padding properties, border properties, color
		property, background properties. UAs may apply other properties as
		well. To allow UAs to render a typographically correct drop cap or
		initial cap, the UA may choose a line-height, width and height based
		on the shape of the letter, unlike for normal elements.

	</p>
	<div class="example">
		<p>Example:</p>

		<p>
			This CSS and HTML example shows a possible rendering of an initial
			cap. Note that the ‘
			<code class="property">line-height</code>
			’ that is inherited by the
			<code>::first-letter</code>
			pseudo-element is 1.1, but the UA in this example has computed the
			height of the first letter differently, so that it doesn't cause any
			unnecessary space between the first two lines. Also note that the
			fictional start tag of the first letter is inside the <span>span</span>,
			and thus the font weight of the first letter is normal, not bold as
			the <span>span</span>:

		</p>
		<pre>p { line-height: 1.1 }
			p::first-letter { font-size: 3em; font-weight: normal }
			span { font-weight: bold }
			...
			&lt;p&gt;&lt;span&gt;Het hemelsche&lt;/span&gt; gerecht heeft zich ten lange lesten&lt;br&gt;
			Erbarremt over my en mijn benaeuwde vesten&lt;br&gt;
			En arme burgery, en op mijn volcx gebed&lt;br&gt;
			En dagelix geschrey de bange stad ontzet.
		</pre>

	</div>

	<div class="example">
		<p>The following CSS will make a drop cap initial letter span
			about two lines:</p>

		<pre>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"&gt;
			&lt;HTML&gt;
			&lt;HEAD&gt;
			&lt;TITLE&gt;Drop cap initial letter&lt;/TITLE&gt;
			&lt;STYLE type="text/css"&gt;
			P               { font-size: 12pt; line-height: 1.2 }
			P::first-letter { font-size: 200%; font-weight: bold; float: left }
			SPAN            { text-transform: uppercase }
			&lt;/STYLE&gt;
			&lt;/HEAD&gt;
			&lt;BODY&gt;
			&lt;P&gt;&lt;SPAN&gt;The first&lt;/SPAN&gt; few words of an article
			in The Economist.&lt;/P&gt;
			&lt;/BODY&gt;
			&lt;/HTML&gt;
		</pre>

		<p>This example might be formatted as follows:</p>

		<p>
			The <span class="index-inst" id="fictional-tag-sequence0"
				title="fictional
																																				tag sequence">fictional
				tag sequence</span> is:
		</p>

		<pre>&lt;P&gt;
			&lt;SPAN&gt;
			&lt;P::first-letter&gt;
			T
			&lt;/P::first-letter&gt;he first
			&lt;/SPAN&gt; 
			few words of an article in the Economist.
			&lt;/P&gt;
		</pre>

		<p>
			Note that the
			<code>::first-letter</code>
			pseudo-element tags abut the content (i.e., the initial character),
			while the ::first-line pseudo-element start tag is inserted right
			after the start tag of the block element.
		</p>
	</div>

	<p>In order to achieve traditional drop caps formatting, user
		agents may approximate font sizes, for example to align baselines.
		Also, the glyph outline may be taken into account when formatting.</p>
	<h3 id="selection">
		<span class="secno">7.3. </span>Blank
	</h3>

	<p>
		This section intentionally left blank. (This section previously
		defined a
		<code>::selection</code>
		pseudo-element.)

	</p>
	<h3 id="gen-content">
		<span class="secno">7.4. </span>The ::before and ::after
		pseudo-elements
	</h3>

	<p>
		The
		<code>::before</code>
		and
		<code>::after</code>
		pseudo-elements can be used to describe generated content before or
		after an element's content. They are explained in CSS 2.1 <a
			href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>.

	</p>
	<p>
		When the
		<code>::first-letter</code>
		and
		<code>::first-line</code>
		pseudo-elements are applied to an element having content generated
		using
		<code>::before</code>
		or
		<code>::after</code>
		, they apply to the first letter or line of the element including the
		generated content.

	</p>
	<h2 id="combinators">
		<span class="secno">8. </span>Combinators
	</h2>

	<h3 id="descendant-combinators">
		<span class="secno">8.1. </span>Descendant combinator
	</h3>

	<p>
		At times, authors may want selectors to describe an element that is
		the descendant of another element in the document tree (e.g., "an
		<code>EM</code>
		element that is contained within an
		<code>H1</code>
		element"). Descendant combinators express such a relationship. A
		descendant combinator is <a href="#whitespace">whitespace</a> that
		separates two sequences of simple selectors. A selector of the form "
		<code>A B</code>
		" represents an element
		<code>B</code>
		that is an arbitrary descendant of some ancestor element
		<code>A</code>
		.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>For example, consider the following selector:</p>

		<pre>h1 em</pre>

		<p>
			It represents an
			<code>em</code>
			element being the descendant of an
			<code>h1</code>
			element. It is a correct and valid, but partial, description of the
			following fragment:
		</p>

		<pre>&lt;h1&gt;This &lt;span class="myclass"&gt;headline
			is &lt;em&gt;very&lt;/em&gt; important&lt;/span&gt;&lt;/h1&gt;</pre>

		<p>The following selector:</p>

		<pre>div * p</pre>

		<p>
			represents a
			<code>p</code>
			element that is a grandchild or later descendant of a
			<code>div</code>
			element. Note the whitespace on either side of the "*" is not part of
			the universal selector; the whitespace is a combinator indicating
			that the
			<code>div</code>
			must be the ancestor of some element, and that that element must be
			an ancestor of the
			<code>p</code>
			.
		</p>

		<p>
			The following selector, which combines descendant combinators and <a
				href="#attribute-selectors">attribute selectors</a>, represents an
			element that (1) has the
			<code>href</code>
			attribute set and (2) is inside a
			<code>p</code>
			that is itself inside a
			<code>div</code>
			:
		</p>

		<pre>div p *[href]</pre>
	</div>

	<h3 id="child-combinators">
		<span class="secno">8.2. </span>Child combinators
	</h3>

	<p>
		A
		<dfn id="child-combinator">child combinator</dfn>
		describes a childhood relationship between two elements. A child
		combinator is made of the "greater-than sign" (U+003E,
		<code>&gt;</code>
		) character and separates two sequences of simple selectors.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following selector represents a
			<code>p</code>
			element that is child of
			<code>body</code>
			:
		</p>

		<pre>body &gt; p</pre>

		<p>The following example combines descendant combinators and child
			combinators.</p>

		<pre>div ol&gt;li p</pre>
		<!-- LEAVE THOSE SPACES OUT! see below -->
		<p>
			It represents a
			<code>p</code>
			element that is a descendant of an
			<code>li</code>
			element; the
			<code>li</code>
			element must be the child of an
			<code>ol</code>
			element; the
			<code>ol</code>
			element must be a descendant of a
			<code>div</code>
			. Notice that the optional white space around the "&gt;" combinator
			has been left out.
		</p>
	</div>

	<p>
		For information on selecting the first child of an element, please see
		the section on the
		<code>
			<a href="#structural-pseudos">:first-child</a>
		</code>
		pseudo-class above.

	</p>
	<h3 id="sibling-combinators">
		<span class="secno">8.3. </span>Sibling combinators
	</h3>

	<p>There are two different sibling combinators: the adjacent
		sibling combinator and the general sibling combinator. In both cases,
		non-element nodes (e.g. text between elements) are ignored when
		considering adjacency of elements.</p>
	<h4 id="adjacent-sibling-combinators">
		<span class="secno">8.3.1. </span>Adjacent sibling combinator
	</h4>

	<p>
		The adjacent sibling combinator is made of the "plus sign" (U+002B,
		<code>+</code>
		) character that separates two sequences of simple selectors. The
		elements represented by the two sequences share the same parent in the
		document tree and the element represented by the first sequence
		immediately precedes the element represented by the second one.

	</p>
	<div class="example">
		<p>Examples:</p>

		<p>
			The following selector represents a
			<code>p</code>
			element immediately following a
			<code>math</code>
			element:
		</p>

		<pre>math + p</pre>

		<p>
			The following selector is conceptually similar to the one in the
			previous example, except that it adds an attribute selector — it adds
			a constraint to the
			<code>h1</code>
			element, that it must have
			<code>class="opener"</code>
			:
		</p>

		<pre>h1.opener + h2</pre>
	</div>

	<h4 id="general-sibling-combinators">
		<span class="secno">8.3.2. </span>General sibling combinator
	</h4>

	<p>
		The general sibling combinator is made of the "tilde" (U+007E,
		<code>~</code>
		) character that separates two sequences of simple selectors. The
		elements represented by the two sequences share the same parent in the
		document tree and the element represented by the first sequence
		precedes (not necessarily immediately) the element represented by the
		second one.

	</p>
	<div class="example">
		<p>Example:</p>

		<pre>h1 ~ pre</pre>

		<p>
			represents a
			<code>pre</code>
			element following an
			<code>h1</code>
			. It is a correct and valid, but partial, description of:
		</p>

		<pre>&lt;h1&gt;Definition of the function a&lt;/h1&gt;
			&lt;p&gt;Function a(x) has to be applied to all figures in the table.&lt;/p&gt;
			&lt;pre&gt;function a(x) = 12x/13.5&lt;/pre&gt;</pre>
	</div>

	<h2 id="specificity">
		<span class="secno">9. </span>Calculating a selector's specificity
	</h2>

	<p>A selector's specificity is calculated as follows:</p>
	<ul>
		<li>count the number of ID selectors in the selector (= a)</li>
		<li>count the number of class selectors, attributes selectors,
			and pseudo-classes in the selector (= b)</li>
		<li>count the number of type selectors and pseudo-elements in the
			selector (= c)</li>
		<li>ignore the universal selector</li>
	</ul>

	<p>
		Selectors inside <a href="#negation">the negation pseudo-class</a> are
		counted like any other, but the negation itself does not count as a
		pseudo-class.

	</p>
	<p>Concatenating the three numbers a-b-c (in a number system with a
		large base) gives the specificity.</p>
	<div class="example">
		<p>Examples:</p>

		<pre>*               /* a=0 b=0 c=0 -&gt; specificity =   0 */
			LI              /* a=0 b=0 c=1 -&gt; specificity =   1 */
			UL LI           /* a=0 b=0 c=2 -&gt; specificity =   2 */
			UL OL+LI        /* a=0 b=0 c=3 -&gt; specificity =   3 */
			H1 + *[REL=up]  /* a=0 b=1 c=1 -&gt; specificity =  11 */
			UL OL LI.red    /* a=0 b=1 c=3 -&gt; specificity =  13 */
			LI.red.level    /* a=0 b=2 c=1 -&gt; specificity =  21 */
			#x34y           /* a=1 b=0 c=0 -&gt; specificity = 100 */
			#s12:not(FOO)   /* a=1 b=0 c=1 -&gt; specificity = 101 */
		</pre>
	</div>

	<p class="note">
		<strong>Note:</strong> Repeated occurrances of the same simple
		selector are allowed and do increase specificity.

	</p>
	<p class="note">
		<strong>Note:</strong> the specificity of the styles specified in an
		HTML
		<code>style</code>
		attribute is described in CSS 2.1. <a href="#CSS21" rel="biblioentry">[CSS21]<!--{{!CSS21}}--></a>.

	</p>
	<h2 id="w3cselgrammar">
		<span class="secno">10. </span>The grammar of Selectors
	</h2>

	<h3 id="grammar">
		<span class="secno">10.1. </span>Grammar
	</h3>

	<p>
		The grammar below defines the syntax of Selectors. It is globally
		LL(1) and can be locally LL(2) (but note that most UAs should not use
		it directly, since it doesn't express the parsing conventions). The
		format of the productions is optimized for human consumption and some
		shorthand notations beyond Yacc (see <a href="#YACC" rel="biblioentry">[YACC]<!--{{!YACC}}--></a>)
		are used:

	</p>
	<ul>
		<li><b>*</b>: 0 or more</li>
		<li><b>+</b>: 1 or more</li>
		<li><b>?</b>: 0 or 1</li>
		<li><b>|</b>: separates alternatives</li>
		<li><b>[ ]</b>: grouping</li>
	</ul>

	<p>The productions are:</p>
	<pre>selectors_group
		: selector [ COMMA S* selector ]*
		;

		selector
		: simple_selector_sequence [ combinator simple_selector_sequence ]*
		;

		combinator
		/* combinators can be surrounded by whitespace */
		: PLUS S* | GREATER S* | TILDE S* | S+
		;

		simple_selector_sequence
		: [ type_selector | universal ]
		[ HASH | class | attrib | pseudo | negation ]*
		| [ HASH | class | attrib | pseudo | negation ]+
		;

		type_selector
		: [ namespace_prefix ]? element_name
		;

		namespace_prefix
		: [ IDENT | '*' ]? '|'
		;

		element_name
		: IDENT
		;

		universal
		: [ namespace_prefix ]? '*'
		;

		class
		: '.' IDENT
		;

		attrib
		: '[' S* [ namespace_prefix ]? IDENT S*
		[ [ PREFIXMATCH |
		SUFFIXMATCH |
		SUBSTRINGMATCH |
		'=' |
		INCLUDES |
		DASHMATCH ] S* [ IDENT | STRING ] S*
		]? ']'
		;

		pseudo
		/* '::' starts a pseudo-element, ':' a pseudo-class */
		/* Exceptions: :first-line, :first-letter, :before and :after. */
		/* Note that pseudo-elements are restricted to one per selector and */
		/* occur only in the last simple_selector_sequence. */
		: ':' ':'? [ IDENT | functional_pseudo ]
		;

		functional_pseudo
		: FUNCTION S* expression ')'
		;

		expression
		/* In CSS3, the expressions are identifiers, strings, */
		/* or of the form "an+b" */
		: [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+
		;

		negation
		: NOT S* negation_arg S* ')'
		;

		negation_arg
		: type_selector | universal | HASH | class | attrib | pseudo
		;</pre>

	<h3 id="lex">
		<span class="secno">10.2. </span>Lexical scanner
	</h3>

	<p>
		The following is the <a name="x3">tokenizer</a>, written in Flex (see
		<a href="#FLEX" rel="biblioentry">[FLEX]<!--{{!FLEX}}--></a>)
		notation. The tokenizer is case-insensitive.

	</p>
	<p>
		The two occurrences of "\377" represent the highest character number
		that current versions of Flex can deal with (decimal 255). They should
		be read as "\4177777" (decimal 1114111), which is the highest possible
		code point in Unicode/ISO-10646. <a href="#UNICODE" rel="biblioentry">[UNICODE]<!--{{!UNICODE}}--></a>

	</p>
	<pre>%option case-insensitive

		ident     [-]?{nmstart}{nmchar}*
		name      {nmchar}+
		nmstart   [_a-z]|{nonascii}|{escape}
		nonascii  [^\0-\177]
		unicode   \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
		escape    {unicode}|\\[^\n\r\f0-9a-f]
		nmchar    [_a-z0-9-]|{nonascii}|{escape}
		num       [0-9]+|[0-9]*\.[0-9]+
		string    {string1}|{string2}
		string1   \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*\"
		string2   \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\'
		invalid   {invalid1}|{invalid2}
		invalid1  \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*
		invalid2  \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*
		nl        \n|\r\n|\r|\f
		w         [ \t\r\n\f]*

		D         d|\\0{0,4}(44|64)(\r\n|[ \t\r\n\f])?
		E         e|\\0{0,4}(45|65)(\r\n|[ \t\r\n\f])?
		N         n|\\0{0,4}(4e|6e)(\r\n|[ \t\r\n\f])?|\\n
		O         o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o
		T         t|\\0{0,4}(54|74)(\r\n|[ \t\r\n\f])?|\\t
		V         v|\\0{0,4}(58|78)(\r\n|[ \t\r\n\f])?|\\v

		%%

		[ \t\r\n\f]+     return S;

		"~="             return INCLUDES;
		"|="             return DASHMATCH;
		"^="             return PREFIXMATCH;
		"$="             return SUFFIXMATCH;
		"*="             return SUBSTRINGMATCH;
		{ident}          return IDENT;
		{string}         return STRING;
		{ident}"("       return FUNCTION;
		{num}            return NUMBER;
		"#"{name}        return HASH;
		{w}"+"           return PLUS;
		{w}"&gt;"           return GREATER;
		{w}","           return COMMA;
		{w}"~"           return TILDE;
		":"{N}{O}{T}"("  return NOT;
		@{ident}         return ATKEYWORD;
		{invalid}        return INVALID;
		{num}%           return PERCENTAGE;
		{num}{ident}     return DIMENSION;
		"&lt;!--"           return CDO;
		"--&gt;"            return CDC;

		\/\*[^*]*\*+([^/*][^*]*\*+)*\/                    /* ignore comments */

		.                return *yytext;
	</pre>

	<h2 id="profiling">
		<span class="secno">11. </span>Profiles
	</h2>

	<p>Each specification using Selectors must define the subset of
		Selectors it allows and excludes, and describe the local meaning of
		all the components of that subset.</p>
	<p>Non normative examples:</p>
	<div class="profile">
		<table class="tprofile">
			<tbody>
				<tr>
					<th class="title" colspan="2">Selectors profile</th>
				</tr>
				<tr>
					<th>Specification</th>
					<td>CSS level 1</td>
				</tr>
				<tr>
					<th>Accepts</th>
					<td>type selectors<br> class selectors<br> ID
						selectors<br> :link, :visited and :active pseudo-classes<br>
						descendant combinator <br> ::first-line and ::first-letter
						pseudo-elements

					</td>
				</tr>
				<tr>
					<th>Excludes</th>
					<td>
						<p>
							universal selector<br> attribute selectors<br> :hover
							and :focus pseudo-classes<br> :target pseudo-class<br>
							:lang() pseudo-class<br> all UI element states
							pseudo-classes<br> all structural pseudo-classes<br>
							negation pseudo-class<br> ::before and ::after
							pseudo-elements<br> child combinators<br> sibling
							combinators

						</p>
						<p>namespaces</p>
					</td>
				</tr>
				<tr>
					<th>Extra constraints</th>
					<td>only one class selector allowed per sequence of simple
						selectors</td>
				</tr>
			</tbody>
		</table>
		<br> <br>

		<table class="tprofile">
			<tbody>
				<tr>
					<th class="title" colspan="2">Selectors profile</th>
				</tr>
				<tr>
					<th>Specification</th>
					<td>CSS level 2</td>
				</tr>
				<tr>
					<th>Accepts</th>
					<td>type selectors<br> universal selector<br>
						attribute presence and values selectors<br> class selectors<br>
						ID selectors<br> :link, :visited, :active, :hover, :focus,
						:lang() and :first-child pseudo-classes <br> descendant
						combinator<br> child combinator<br> adjacent sibling
						combinator<br> ::first-line and ::first-letter
						pseudo-elements<br> ::before and ::after pseudo-elements

					</td>
				</tr>
				<tr>
					<th>Excludes</th>
					<td>
						<p>
							substring matching attribute selectors<br> :target
							pseudo-classes<br> all UI element states pseudo-classes<br>
							all structural pseudo-classes other than :first-child<br>
							negation pseudo-class <br> general sibling combinators

						</p>
						<p>namespaces</p>
					</td>
				</tr>
				<tr>
					<th>Extra constraints</th>
					<td>more than one class selector per sequence of simple
						selectors (CSS1 constraint) allowed</td>
				</tr>
			</tbody>
		</table>

		<p>In CSS, selectors express pattern matching rules that determine
			which style rules apply to elements in the document tree.</p>
		<p>
			The following selector (CSS level 2) will <b>match</b> all anchors
			<code>a</code>
			with attribute
			<code>name</code>
			set inside a section 1 header
			<code>h1</code>
			:

		</p>
		<pre>h1 a[name]</pre>

		<p>All CSS declarations attached to such a selector are applied to
			elements matching it.</p>
	</div>

	<div class="profile">
		<table class="tprofile">
			<tbody>
				<tr>
					<th class="title" colspan="2">Selectors profile</th>
				</tr>
				<tr>
					<th>Specification</th>
					<td>STTS 3</td>
				</tr>
				<tr>
					<th>Accepts</th>
					<td>
						<p>
							type selectors<br> universal selectors<br> attribute
							selectors<br> class selectors<br> ID selectors<br>
							all structural pseudo-classes<br> all combinators

						</p>
						<p>namespaces</p>
					</td>
				</tr>
				<tr>
					<th>Excludes</th>
					<td>non-accepted pseudo-classes<br> pseudo-elements<br>

					</td>
				</tr>
				<tr>
					<th>Extra constraints</th>
					<td>some selectors and combinators are not allowed in fragment
						descriptions on the right side of STTS declarations.</td>
				</tr>
			</tbody>
		</table>

		<p>Selectors can be used in STTS 3 in two different manners:</p>
		<ol>
			<li>a selection mechanism equivalent to CSS selection mechanism:
				declarations attached to a given selector are applied to elements
				matching that selector,</li>
			<li>fragment descriptions that appear on the right side of
				declarations.</li>
		</ol>
	</div>

	<h2 id="Conformance">
		<span class="secno">12. </span>Conformance and requirements
	</h2>

	<p>This section defines conformance with the present specification
		only.</p>
	<p>The inability of a user agent to implement part of this
		specification due to the limitations of a particular device (e.g., non
		interactive user agents will probably not implement dynamic
		pseudo-classes because they make no sense without interactivity) does
		not imply non-conformance.</p>
	<p>
		All specifications reusing Selectors must contain a <a
			href="#profiling">Profile</a> listing the subset of Selectors it
		accepts or excludes, and describing the constraints it adds to the
		current specification.

	</p>
	<p>Invalidity is caused by a parsing error, e.g. an unrecognized
		token or a token which is not allowed at the current parsing point.</p>
	<p>User agents must observe the rules for handling parsing errors:

	</p>
	<ul>
		<li>a simple selector containing an <a href="#nsdecl">undeclared
				namespace prefix</a> is invalid

		</li>
		<li>a selector containing an invalid simple selector, an invalid
			combinator or an invalid token is invalid.</li>
		<li>a group of selectors containing an invalid selector is
			invalid.</li>
	</ul>

	<p>Specifications reusing Selectors must define how to handle
		parsing errors. (In the case of CSS, the entire rule in which the
		selector is used is dropped.)</p>
	<h2 id="Tests">
		<span class="secno">13. </span>Tests
	</h2>

	<p>
		This specification has <a
			href="http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/">a
			test suite</a> allowing user agents to verify their basic conformance to
		the specification. This test suite does not pretend to be exhaustive
		and does not cover all possible combined cases of Selectors.

	</p>
	<h2 id="ACKS">
		<span class="secno">14. </span>Acknowledgements
	</h2>

	<p>The CSS working group would like to thank everyone who has sent
		comments on this specification over the years.</p>
	<p>In particular, the working group would like to extend special
		thanks to Donna McManus, Justin Baker, Joel Sklar, and Molly Ives
		Brower who performed the final editorial review of the last call
		draft. The working group would also like to thank Adam Kuehn, Boris
		Zbarsky, David Perrell, Elliotte Harold, Matthew Raymond, Ruud
		Steltenpool, Patrick Garies, Anton Prowse, and the W3C
		Internationalization Working Group for their last call comments and
		kind words.</p>
	<h2 id="references">
		<span class="secno">15. </span>References
	</h2>

	<h3 id="normative-references">
		<span class="secno">15.1. </span>Normative References
	</h3>
	<!--begin-normative-->
	<!-- Sorted by label -->

	<dl class="bibliography">
		<dt style="display: none">
			<!-- keeps the doc valid if the DL is empty -->
			<!---->

		</dt>
		<dt id="CSS21">[CSS21]</dt>
		<dd>
			Bert Bos; et al. <a href="http://www.w3.org/TR/2009/CR-CSS2-20090908"><cite>Cascading
					Style Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 07 June
			2011. W3C Recommendation. URL: <a
				href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">http://www.w3.org/TR/2011/REC-CSS2-20110607/</a>
		</dd>
		<!---->

		<dt id="CSS3NAMESPACE">[CSS3NAMESPACE]</dt>
		<dd>
			Elika J. Etemad; Anne van Kesteren. <a
				href="http://www.w3.org/TR/2011/REC-css3-namespace-20110929/"><cite>CSS
					Namespaces Module.</cite></a> 29 September 2011. W3C Recommendation. URL: <a
				href="http://www.w3.org/TR/2011/REC-css3-namespace-20110929/">http://www.w3.org/TR/2011/REC-css3-namespace-20110929/</a>
		</dd>
		<!---->

		<dt id="FLEX">[FLEX]</dt>
		<dd>
			<cite>Flex: The Lexical Scanner Generator.</cite> Version 2.3.7, ISBN
			1882114213
		</dd>
		<!---->

		<dt id="UNICODE">[UNICODE]</dt>
		<dd>
			The Unicode Consortium. The Unicode Standard, Version 6.0.0,
			(Mountain View, CA: The Unicode Consortium, 2011. ISBN
			978-1-936213-01-6) and as updated from time to time by the
			publication of new versions. (See <a
				href="http://www.unicode.org/unicode/standard/versions/">
				http://www.unicode.org/unicode/standard/versions/</a> for the latest
			version and additional information on versions of the standard and of
			the Unicode Character Database).<br> Available at <a
				href="http://www.unicode.org/versions/Unicode6.0.0/">
				http://www.unicode.org/versions/Unicode6.0.0/</a>
		</dd>
		<!---->

		<dt id="YACC">[YACC]</dt>
		<dd>
			S. C. Johnson. <cite>YACC - Yet another compiler compiler.</cite>
			Murray Hill. 1975. Technical Report.
		</dd>
		<!---->
	</dl>
	<!--end-normative-->

	<h3 id="informative-references">
		<span class="secno">15.2. </span>Informative References
	</h3>
	<!--begin-informative-->
	<!-- Sorted by label -->

	<dl class="bibliography">
		<dt style="display: none">
			<!-- keeps the doc valid if the DL is empty -->
			<!---->

		</dt>
		<dt id="BCP47">[BCP47]</dt>
		<dd>
			A. Phillips; M. Davis<a
				href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt"><cite>Tags
					for Identifying Languages</cite> and <cite>Matching of Language
					Tags</cite>.</a> September 2009. Internet Best Current Practice 47. URL: <a
				href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt">http://www.rfc-editor.org/rfc/bcp/bcp47.txt</a>
		</dd>
		<!---->

		<dt id="CSS1">[CSS1]</dt>
		<dd>
			Håkon Wium Lie; Bert Bos. <a
				href="http://www.w3.org/TR/2008/REC-CSS1-20080411"><cite>Cascading
					Style Sheets (CSS1) Level 1 Specification.</cite></a> 11 April 2008. W3C
			Recommendation. URL: <a
				href="http://www.w3.org/TR/2008/REC-CSS1-20080411">http://www.w3.org/TR/2008/REC-CSS1-20080411</a>
		</dd>
		<!---->

		<dt id="DOM-LEVEL-3-CORE">[DOM-LEVEL-3-CORE]</dt>
		<dd>
			Gavin Nicol; et al. <a
				href="http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407"><cite>Document
					Object Model (DOM) Level 3 Core Specification.</cite></a> 7 April 2004. W3C
			Recommendation. URL: <a
				href="http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407">http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407</a>
		</dd>
		<!---->

		<dt id="HTML401">[HTML401]</dt>
		<dd>
			David Raggett; Ian Jacobs; Arnaud Le Hors. <a
				href="http://www.w3.org/TR/1999/REC-html401-19991224"><cite>HTML
					4.01 Specification.</cite></a> 24 December 1999. W3C Recommendation. URL: <a
				href="http://www.w3.org/TR/1999/REC-html401-19991224">http://www.w3.org/TR/1999/REC-html401-19991224</a>
		</dd>
		<!---->

		<dt id="MATHML">[MATHML]</dt>
		<dd>
			Patrick Ion; Robert Miner. <a
				href="http://www.w3.org/1999/07/REC-MathML-19990707"><cite>Mathematical
					Markup Language (MathML) 1.01 Specification.</cite></a> 7 July 1999. W3C
			Recommendation. URL: <a
				href="http://www.w3.org/1999/07/REC-MathML-19990707">http://www.w3.org/1999/07/REC-MathML-19990707</a>
		</dd>
		<!---->

		<dt id="STTS3">[STTS3]</dt>
		<dd>
			Daniel Glazman. <a href="http://www.w3.org/TR/NOTE-STTS3"><cite>Simple
					Tree Transformation Sheets 3.</cite></a> Electricité de France. 11 November
			1998. Submission to the W3C. URL: <a
				href="http://www.w3.org/TR/NOTE-STTS3">http://www.w3.org/TR/NOTE-STTS3</a>
		</dd>
		<!---->

		<dt id="SVG11">[SVG11]</dt>
		<dd>
			Erik Dahlström et. al. <a
				href="http://www.w3.org/TR/2011/REC-SVG11-20110816/"><cite>Scalable
					Vector Graphics (SVG) 1.1 Specification.</cite></a> 16 August 2011. W3C
			Recommendation. URL: <a
				href="http://www.w3.org/TR/2011/REC-SVG11-20110816/">http://www.w3.org/TR/2011/REC-SVG11-20110816/</a>
		</dd>
		<!---->

		<dt id="UAX29">[UAX29]</dt>
		<dd>
			Mark Davis. <a
				href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html"><cite>Text
					Boundaries.</cite></a> 25 March 2005. Unicode Standard Annex #29. URL: <a
				href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html">http://www.unicode.org/unicode/reports/tr29/tr29-9.html</a>
		</dd>
		<!---->

		<dt id="XML-NAMES">[XML-NAMES]</dt>
		<dd>
			Tim Bray; et al. <a
				href="http://www.w3.org/TR/2009/PER-xml-names-20090806"><cite>Namespaces
					in XML 1.0 (Third Edition).</cite></a> 6 August 2009. W3C Proposed Edited
			Recommendation. URL: <a
				href="http://www.w3.org/TR/2009/PER-xml-names-20090806">http://www.w3.org/TR/2009/PER-xml-names-20090806</a>
		</dd>
		<!---->

		<dt id="XML10">[XML10]</dt>
		<dd>
			C. M. Sperberg-McQueen; et al. <a
				href="http://www.w3.org/TR/2008/PER-xml-20080205"><cite>Extensible
					Markup Language (XML) 1.0 (Fifth Edition).</cite></a> 10 February 1998. W3C
			Proposed Edited Recommendation. Revised 5 February 2008 URL: <a
				href="http://www.w3.org/TR/2008/PER-xml-20080205">http://www.w3.org/TR/2008/PER-xml-20080205</a>
		</dd>
		<!---->
	</dl>
	<!--end-informative-->

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